(technical) LJ gripe

I noticed that when I join a community, and choose to watch it as well as just joining via that checkbox, some communities still won't appear automatically on my friends page and I have to manually configure this via the filter options, whereas other communities appear right away, without any extra effort on my part. This behavior is confusing, also I'm likely to miss posts in a community after joining, thinking there are none, because none appear on my friends page, until I notice that there aren't any posts for days. I mean I don't reconfigure the filter options all that often (if it weren't for this problem I wouldn't have looked at them at all, especially since I don't really use filters due to the moderate number of journals I read). Had anyone else experiences with this? I'm wondering if that behavior is an option the community founder sets, and whether I can tell what will happen, or whether it is random glitches, nobody can predict?