Correct, this is not a legal name change. Not even in India.
When I submitted for correction, I had written to Indian consulate that my Passport application was erroneously filled, as such complete name is in first name. Now I need to split it.
upon receiving the updated passport, I sent similar letter to IRCC with copies of letter submitted to Indian consulate and other necessary forms and docements.
you are only splitting your name, not legally changing it.
Thank you, I didn't know the legal background of this in India (that they will consider this a correction).
However: I think this 'correction' should be approached as a name change from a Canadian legal perspective - with the caveat that I'm not certain about this, and i'm not certain that this distinction matters at all.
I think the Cdn legal perspective would be that 'corrections' like typos should only be for cases of manifest error (something like spelling the famly name 'Smith' as 'Quith') and corrected quickly - as eg IRCC does for mistakes on PR cards and cit certificates and the like - you HAVE to get the change done within a certain period of time. Because if you didn't get it fixed quickly, you
used that name.
At any rate, the 'solution' should be the shame - show the documents you had (ideally including the submission requesting the name be split and the response), and get Canadian authorities to recognize that this is effectively a change of name. (Note, with a change of name, you are NOT required to get all documents replaced, and some - like COPR and birth certificates - will not be changed retroactively; you can usually just use old doc + chnage of name evidence, although much more convenient if all eventually get changed.)
Again, my belief is that airport check-in counters are likely to be the main issue, because they're cautious, not experts in documents or legal stuff, don't like to make decisions, and it costs them money if they screw up. You can try asking the airline but that may not give much more comfort than generality.
This will be much easier if it's obvious like a simple name split or minor spelling discrepancy (eg with names that have been transliterated from other alphabets).
Your point about making sure to list 'aliases / other names' is a good one.