Well I actually just experienced a similar issue with FireFox 2.0 on my own site. I suppose it could have been a fluke or some other lag - but thought I would mention it in case anyone else runs into similar issue with FF as well.

Overall FF (for what ever reason) is better for use with UBBT (imho) than IE6,7 Though I don't like how FF views some other sites I suppose it's a trade off.