When you say this is "FIP-like", can you elaborate? What symptoms of it are like those of FIP? I have a DLH cat who has shivers/muscular contractions when she lays down. It only happens at that point: laying/resting and before actually falling into a deep sleep. It was thought she might have FIP when she was checked out as a kitten, but the test came back negative (though I have heard the tests are useless anyway and often have false positives).
Anyway, she is now 1 1/2 yrs old, and other symptoms are starting to appear. I'm getting ready to take her to the vet yet again but am tired of getting nowhere with vets. I've found a number of people online whose cats have the same issue and get no answers from the vet. My cats brother also has the same issue. So far I'm noticing that all the cats have long hair. I have her videos on youtube if you care to watch:
https://www.youtube.com/watch?v=R8UFsNmLaycI'd appreciate someone on here indicating if this could be what you're seeing in your Bengals. Maybe it's way beyond the purebreds at this point! :( The vets are clueless and whatever this is, it seems to be a growing problem.