incorporating an animation video clip into imovie on my iphone

Hi,
imovie beginner here. I just added an animation clip to my imovie video on my iphone. this is the only clip I am having trouble with. I downloaded it from Pond to my desk top then downloaded it to to my google drive and copied it to my imovie video. I edited the clip with slow motion and trimmed it. It is not consistent in playback and blacks out randomly.

Can anyone help with this?

Anahata

Was the animation slow motion to begin with?
if not, that is probably the problem. Making it slow motion adds frames that aren't there originally.
Which ends up with stuttering and other artifacts.

I don't know anything about Imovie but this would be an issue no matter what editing software you use.

Jake