I did that five times before remembering I had an old account on this instance that I could switch to to post the question and see what communities I used to be subscribed to.
I have a lot of issues with Lemmy and more specifically how the fediverse will work with multiple copies of communities and the knee-jerk defederation. But, in terms of stability, content and quality, I feel like it has been getting better. I'm willing to give it some more time.
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.
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.
I did that five times before remembering I had an old account on this instance that I could switch to to post the question and see what communities I used to be subscribed to.