Granted, we're hardly authoritative sources ourselves here on the BBS, but in various threads we've tried to agree on definitions that define "canon" as what's appeared on-screen, and then distinguish canon from "continuity," which constitutes the events that exist in-universe in history. Under those definitions, ideally, everything in canon would be in continuity, but it's not always reasonable (or desirable) to make that possible.
If those are your definitions, then TAS is canon, but not everything that happens needs to exist in continuity.
"Spock's Brain" is sometimes cited as an example. It's clearly canon, but did events happen just as they were depicted in that episode? Goodness, I hope not. I could imagine something similar, and what we saw on TV was just an over-the-top interpretation of those events, so to speak.
If those are your definitions, then TAS is canon, but not everything that happens needs to exist in continuity.
"Spock's Brain" is sometimes cited as an example. It's clearly canon, but did events happen just as they were depicted in that episode? Goodness, I hope not. I could imagine something similar, and what we saw on TV was just an over-the-top interpretation of those events, so to speak.