It is only relevant in the PH - CEM just wants to make certain that Ma. (your name) and Maria (your name) are one and the same person. Part of security checks. In the PH the general understanding was "Ma." is an abbreviation for "Maria" and can be used interchangeably - however, other countries do not have that understanding, thus problems with initial travelers/immigrants in the early days. Thus came the advise to follow what is in the BC and adjust records accordingly to prevent any issues in the future. This came to be that "Ma." is now different from "Maria".
Since you have traveled before, and have a PP issued with "Maria" and other records reflecting your name as shown in the PP, then preponderance of records will lean towards "Ma." as acceptable abbrev. of "Maria" as in your case. The request for another NBI certificate is in my view, to make sure that "Ma. (your name)" and "Maria (your name)" - with the same biometric info and pertaining to the same person - does not have any record under both names. All clear.
With the influx of immigrants with different names, Canada has also adjusted. Note that here the Middle Name is not used, whereas we use it as a Middle initial, and it was only recent that they have adjusted their systems to reflect the middle name. This is why in the application forms, it is advised to put First Name + Middle Name - as the complete First Name - so as to match what is shown in our passports and avoid confusion in the early stages of the application process.
Congratulations on PPR!
(apologize for not answering your posts sooner - was on vacation in MNL...)
/..atb