UE 4.21 iOS Screen blackout glitch

We have recently upgraded out project from 4.19 to 4.21 and have been experiencing screen blackouts in a distribution / development builds for iOS. When looking in certain directions in some levels now; the entire screen will go black with only the on screen widgets still displaying. Everything still runs fine, and when i turn the camera away the game returns to normal rendering.

Here is a short clip showing the error when i look at an object in a certain direction. I demonstrate before activating this object, i can look at it normally, but after chaining the material in game, my screen will go black when looking at the object in a specific direction. Both materials are almost identical in the editor, and there’s nothing that stands out to me as to why this error is happening.

Has anyone else been having this issue since upgrading to the latest engine version ???

Hey we’ve also noticed same thing from updating our project to 4.21.

Have you figured out what it is?

I have a hunch that it’s related to using a Skylight on any other setting than static on mobile.

Hey, Yeah we did end up figuring it out! i apologize i didn’t update this post before.

It turned out that since the update, any level that we had the sun shaft effect turned on from the directional light, it would cause the screen blackout as soon as a translucent material (glass, plastic, etc.) would come into the screen. Something about the iOS rendering glass like meshes and the new update didn’t mix. Since the sun shaft barely showed up as it is on mobile, we turned it off completely. Since disabling the sun shaft effects, the screen blackouts stopped completely!

Hope this helps.

Thanks so much. This fixed the issue for us too now. We turned off the Light Shafts settings from our Directional lights and no more issues. For future people it’s these values:

Thanks again !