Well if the problem is evident in Ultimate Unwrap, that means there are a few blank frames at the end which I was suggesting trimming off. In short, the pause is actually part of the animation, and I'm suggesting removing that end bit of the animation.
Imagine if in 3ds max at the end of the animation, after the fan turns 360, there are a few more frames of nothing before the animation loops.
I don't know why exactly that is happening, but that's because I've never used the UU exporter for 3ds max. I'm guessing you are exporting a few additional frames without realizing it; perhaps the exporter has a setting for what frames to include.
Imagine if in 3ds max at the end of the animation, after the fan turns 360, there are a few more frames of nothing before the animation loops.
I don't know why exactly that is happening, but that's because I've never used the UU exporter for 3ds max. I'm guessing you are exporting a few additional frames without realizing it; perhaps the exporter has a setting for what frames to include.