Yes, it could just be an error... I've seen a few posts today in different threads that all say that their status updates are showing incorrect updates, so it might be the system glitch. Keep checking your email just in case it is a request for documents.
As for my proof, I included a statement of intent in our original application and some evidence of housing research/planning but since we were not very far ahead in our moving plans at that time, I made it clear in my statement that I can supply updates and more evidence if they need it, as we progress further with our moving plans. Sure enough, they requested additional info around the time that my husband's (PA) application started undergoing background check and eligibility, and just after they sent him the Pre-arrival letter. I have already been approved as a sponsor, so part of me wondered if this was just a formality with certain applications.
As for the additional documents for proof of intent, I included an updated statement; a letter of support from my brother and one from my aunt, who both live in Canada; a letter from my husband's employer (Starbucks) stating his knowledge of our plan to move together and his support for helping my husband transfer to a Canadian location since it's an international company; copies of emails between me and my family discussing my moving plans; samples of apartment & job searches and email inquiries/responses from rental properties; copies of flight itinerary from two recent trips to my hometown of Toronto (where we intend to live) to visit family; and a couple other documents showing support of our plans... it sounds like a lot that I included, but it's because I haven't lived in Canada since I moved away with my father, brother, and stepmom when I was a teenager, so since I've never lived in Canada as a legal adult, I didn't have the same kind of proof that some citizens abroad might have, such as owning property or having a bank account or a former job that they plan to return to. Either way, I feel like there's only so much proof you can have when the timing and details of your move to Canada is dependent on when your spouse gets approved...I can't accept a job yet or sign a lease just yet because we don't know our exact move date until he gets confirmation of PR.
This whole process really keeps you in limbo, doesn't it?