Issues with animated gifs that play only once and .mov files

Hi there!

I'm working on a project where several pages contain animated diagrams that are interactive. The user needs to click on certain areas to see different functions. I created the animations in Animate and exported the frames as png's and then made an animated gif in Photoshop (if I export the gif directly from Animate the colours are not accurate enough). 

If I set the loop setting to "forever", the gif works perfectly, but if I set it to "play once" the gif just pops right to the end frame. Also, it loses transparency on the "play once" setting.

I substituted the gifs with .mov files that I exported directly from Animate, but they are glitchy. The .mov file play a couple of frames and then skip back to the beginning and then play through. 

Has anyone else encountered this? And is there a better file format I could use that would play once smoothly as well as retain transparency features? Unfortunately I can't attached examples due to the nature of the project...