Blinking GIF files in Storyline / GIF blinks when looping

On some projects I need to use transparent GIFs. In most cases, there are no issues. However, sometimes, and for what seems like no reason, when a transparent GIF completes it's animation cycle, it blanks out. It looks like there's a frame (or several) where there's nothing, and then it blinks back and loops. 

I made the GIFs myself, so it's not a question of if there is a blank frame or two. It only happens to certain GIFs as well, and sometimes at random. However, when this happens, the GIF is stuck with the blinking issue.

For example, there is a GIF of a bee flying up and down with flapping wings on a continuous 30 frame loop. The original, without the flapping wings, works fine. However, I went into the original file and made the wings flap/flutter, exported it with the same exact settings, and now it freaks out. 

I've tried seven different methods of exporting, and none of them fixed the blinking issue at the end of the loop. When I tried to just simply extend the GIF out by duplicating the frames, it caused the GIF in Storyline to start blinking and glitching at random intervals. 

Any advice or best practices on importing GIFs into Storyline for looping purposes?