My team is running into an issue where our animated content flashes white before playing on iOS devices; we do not experience the issue on Android devices. The animations were created with Animate CC and exported as .OAM files. The stage background is set to transparent.
The animations were then placed into InDesign as Web Content overlays. The animation frame within InDesign is set to 0% opacity. The poster image is a PNG with a transparent background. The Web Content overlay is set to Auto Play with a .125 second delay and Transparent Background is checked.