Oh wait, I think it's a bug of some kind.
Those comments still exist, for example: https://lemmy.ca/post/49431976/18232436
In the web UI, when viewing your profile, if you keep clicking 'Next', you will eventually see those other comments. Same as if you filter to only display the comments.
For some reason, when viewing your profile, Lemmy is interspersing your old posts at incorrect spots. I don't see anything wrong in the database for those posts, so it's weird that both the main Web UI and your app is doing that. I'll check with the other admins to see what might be happening there.