Sadly, yeah. An example is one of my old Multifandom RPs, The Only Way To Go Is Up. It was one of my successful RPs in a while, and due to the move, every post in that RP went apeshit. I hope it wouldn't happen again to other RPs.
RpNation
Thepotatogod
Kaerri
No content was lost. However, because IPS didn't translate the BBcode properly, most of the posts that had it were left with the raw code sitting in the post, making them hard to read.