I don't think water parameters are the issue as I have another BTA which has been happy and healthy for a few months. the tank (20 gallons) is more that 2 years old, and everything seems very stable. I might do a water change soon (I'm leaving town for a bit).
Lighting is AI prime HD about 6 inches above the surface, so I don't have it at very high intensity (again, the other RBTA is doing fine)
When I got the anemones (about 2 months apart), they stayed away from each other, but about a week ago, the other nem (black widow, not rainbow/rose like the one that's been moving around - I know, my bad) moved slightly into the rainbow one's tentacles and I think they had a bit of a stinging match. the rainbow moved and hasn't really found a place yet. some days, it'll stay shut until after 12:00, and when it opens, it will occasionally have deflated tentacles (it seems to perk up after I feed it, but maybe I'm stressing it out more, idk)
Sorry this is a lot of info and its not really organized, but hopefully it's useful
I should mention I feed both of the anemones NLS fish pellets, which they seem to love and react very strongly to.
tank mates are a just a pair of Ocellaris clownfish and the female is the only one which has been hosted by the anemone (only the rainbow bubble tip) which might be aggravating it a bit. She's pretty aggressive in her hosting and she's a pig who would keep eating until she popped, so she tries to get the pellets from inside the anemone (but usually gives up after a minute)
Again, thanks for all of your feedback and help.
I'll post pictures of before and after shortly.