well, when I 'fix' them, I just removed the last frame, and mabye second to last(in Koromori's case)
I avoid it by putting the frames in a paint file, then find where the 1st frame repeats, then I remove all other frames (same thing for the 'action' frames)then in BMG, I make the idle that would loop, and then copy all of them (usually 10 or so) and paste them 3 times, then I put in the action frames, then I select all and set it to 5, and transparent.