I am not an expert and I am not qualified to offer personal advice.
Moreover, as I responded in the other posts about suspended applications, I do not know how an applicant knows the application is suspended. I am not sure how this would show up in a typical GCMS report to clients. Official cases appear to involve many applicants who did not find out their application had been formally suspended until years after a Citizenship Officer had indeed formally decided to suspend the application pursuant to Section 13.1 in the Citizenship Act.
So I do not know what "ON HOLD" means in particular, and especially so in your specific case.
I believe there can be many reasons or circumstances in which an application is, in a sense, as a matter of practice, "on hold," waiting for someone to do this or that, or waiting for this or that to happen. Applicants who are, as they say, waiting for an updated clearance, for example, can sometimes wait quite awhile.
That is NOT a suspended application. But whether or not the reference to "ON HOLD" in your case is a reference to having suspended the application,
I do not know.
Actually you are the one who should have a good idea. Do you have a background which could explain security concerns? are there reasons for suspecting you are a member of an organized criminal entity? are you a PR-refugee who has obtained a home country passport or traveled to the home country? have you been reported for a breach of the PR Residency Obligation or are you the subject of an inadmissibility proceeding for serious criminality? is there a reason why you might be the subject of an investigation into immigration fraud? If you can confidently, soundly answer NO to all these questions, the odds are very good your application was NOT SUSPENDED pursuant to Section 13.1 in the Citizenship Act. But, rather, was on some sort of administrative hold waiting for this or that . . . to receive a response for an inter-agency inquiry perhaps, such as CBSA or CRA . . . or as previously noted, on hold waiting for an updated clearance from the RCMP or CSIS . . . way too many possibilities to enumerate even a representative sample.
IMPACT ON TIMELINE:
Assuming you applied AFTER October 10, 2017, there is NO REASON to expect progress on the application until later this year. Many of these applications are almost certainly NOT going to get through the process before early 2019. Lots and lots of impatience otherwise rampant in the forum. Floods of unrealistic expectations. As I have oft reminded: in ordinary times the ROUTINE applicant can anticipate reaching the oath in about TWO to THREE times as long as it takes the faster applications. Unfortunately many see the faster timelines and expect theirs should be on that track. Could be. If your application is good to go, next step could happen real soon, and the oath not much later. BUT for many more, it will be TWICE as long or THREE times as long.
But then these are not ordinary times. There was a huge surge of applications in October, November, and December. The surge may have continued, probably to a lesser degree, into this year. On top of that IRCC is a big bureaucracy and bureaucracies are not nimble in adopting and adapting to changes, and the reason for the late 2017 surge in application was major changes in the requirements. The fact that scores of applicants who filed since October 11, 2017 are likely to encounter not just the 12 month timeline for processing applications prior to the surge, but probably some additional time, SHOULD BE PATENTLY OBVIOUS. But posting in this forum suggests scores are oblivious to reality and riding hard fantastical expectations.
Which again is not to say you will have to wait long. I do not know. Forecasting the timeline for individual applicants is a fool's game. Things could happen real soon. Or not until significantly later in the year. A five year old's guess is as good as anyone's here.
Observations regarding GCMS notes:
Generally most ATIP generated copies of a GCMS report for clients are useless. Easily misunderstood. Rife with default codes or blank fields. Key information redacted. And even when there is actual information not otherwise deducible, that information is typically of little or no actual use. Even if it is somewhat interesting, there is rarely any action for an applicant to take based on the information.
Remember, in addition to knowing all the information submitted in the application, the applicant knows ALL the relevant facts, and with even a relatively cursory familiarity with the process should be able to predict the risk of problems and otherwise deduce where the application is at in the process at any given time . . . which, once the application is "IP," but not yet scheduled for the test, the application is almost always simply in a queue in the local office waiting for the assigned processing agent to take the next action, which is to review the application in preparation for and scheduling of the test and program integrity interview. After the test and interview, if the oath is not scheduled right away and eCas does not soon show Decision Made, there is NO great mystery: with exceptions (largely predictable exceptions) the application is again in a queue, probably waiting for the Citizenship Officer to review the application in conjunction with reviewing the processing agent's or interviewer's notes and observations, with perhaps some additional inquiry or two. For the vast majority of qualified applicants who have no reason to think they screwed up the application, there is NOTHING to worry about. For many this goes fast. For many more, not so fast. Nothing much (other than qualifying for urgent processing) an applicant can do to speed things up.
Generally NO ATIP necessary. Just patience.
Take your situation. So you learned in response to the ATIP your application was on hold. So what? Then you learned now its not, all is well to move on. Again, so what? Either way you are still waiting, and having just applied within the last nine or ten so months, and given the surge likely slowing things down, you may have to wait several more months . . . or things could happen real soon.
All ROUTINE qualified applicants really need to know is (1) when the application has AOR (this actually is not necessary, but almost everyone wants reassurance the application is on file and will be processed), (2) if it is necessary to provide any additional information or documents (so proper contact information is critical), (3) notice for when the test and interview are scheduled, and (4) notice for when and where to take the oath.
That is it. Really. Sure, those with non-routine applications have a wrinkle or so to wrangle with. But the vast majority can send in the application, watch for notices and respond accordingly, prepare for and show up for the test and interview, and then watch for notice of the oath and show up, raise your right hand, give allegiance to the Queen, and duly celebrate.
Or, if one prefers, hover over the computer daily checking eCas, spend hours on hold waiting to talk to call centre representatives, fret over how long it is taking for eCas to show IP, fret over whether the file actually is in the local office or not, fret over which local office is processing the application, work your ulcers hard agonizing over no notice for the test when someone else is already taking the test and they applied later, shoot of some ATIP requests, work the ulcers over some more trying to interpret the GCMS notes (which mostly simply state: yep, your application is in process).
Hopefully you will see the next step happen real soon. If not, odds are good all is well anyway and you will get notice of the next step in due course. Not to worry. 
