Have you checked the behaviour of those comments on the web or in another app? I've definitely seen this but I'm somewhat used to it from RIF. I always figured it meant the comments were deleted after the initial pull of the data.
The comments are not being deleted, the parent comments and mine still exist and occasionally can be accessed by the app. I dont run into the issue on browser but 95% of my lemmy use is on connect. I have not checked their behavior in another app. I personally never experienced these issues in RIF.
I imagine specific examples would help the devs. If you can point to a post and comments that disappear in Connect but show up fine in a browser, it would give them a place to debug.
I do have a screen capture of clicking on a comment from my profile and the issue happening. I'll see if i can email them the video.
A community for the mobile app Connect for Lemmy.