So I have been dealing with this issue for a few months now and still have not found a cause to the problem. I’ve been working on simple animations that are using alpha inverted matte layers. I double checked to make to make sure that alpha inverted mattes are supported before building the animations. But for some reason the animation is not playing correctly on the LottieFiles iOS app. The alpha inverted matte is not displaying as intended. On android, iOS mobile browsers and desktop the animation plays correctly. Here is a link for one of the animations. https://lottiefiles.com/share/mhcGYB
Here is a screenshot of one of my animations on iOS. You can see that the edges of the alpha inverted matte layers are blurry and pixelated. This screenshot is from a different animation not the one linked above. Though the animations have the same alpha inverted matte effect.
I should also note that I did test the animation on another Lottie player iOS app called Lottie Samples. This test worked as the animation did not display the blurring artifacts like the screenshot above. Test the animation link on this app for yourself.
I tried using mask paths instead of track matte layers but that doesn’t work for this particular animation. So maybe the LottieFiles iOS app has a bug in this particular case? Since my second iOS app test proved to work fine then this is the only conclusion I can come up with. Please tell me your thoughts.