Beta 5 is available, not much is changed but it is more sensitive to changes in groups even when the number of raid members stays the same.
Basically an optimisation has been removed and it is more like an older version of healbot on group/raid change events.
See the Screen Shot you can see I dont have Fortitude and the Warning Colour is the same as my Bar Colour but it isnt suppose to be its meant to be White but it keeps changing itself to my active bar colour when it fucks up and I cant change it back, also at this point it stops tracking Magic Debuff too, This happened now when i changed group in a man. Did WM then changed to a TD group and it fucked up, this is what happens in Raids too. I hope this helps.