HTML5 Video element on IPhone has border

Question

I have been building an app recently and have a loading animation playing at the start (just a mp4 video - for aesthetic purposes). It works great everywhere apart from on Iphon

Answer 1

I tried that on iOS 12 installed iPad WiFi 2017 on Safari and things were all good. Do you have any chance to video that glitch with another recording device?

Edit: General appearance cleaner -webkit-appearance: none may do the trick.