Hi ​@Tammy_Hu1, Thanks for reaching out about this!
 

I noticed the white square section outside the phone frame is visible in the second image.

Looking at the first picture, it seems you're using a GIF in your slide. I was able to reproduce the same behavior using a GIF, which suggests this may be a limitation of the feature. 

Could you try using a static image instead and see if that fixes it?

I'll check with the team and let you know if we find anything out.

Thanks again for contacting us!

That’s correct it’s a GIF, static images are fine but I need a GIF for the purposes of this deck. I don’t have access to putting in a video because it’s paywalled, and for the sake of presentation would prefer not to embed a prototype.