The cubemaps are generated with a simple Sphere Reflection Capture. We also use a post-process environmental cubemap, but I was able to duplicate the effect on an example scene with Sphere Reflection Captures.
are screenshots of a chromeball when the player is idle (the funny thing is the idle animation doesn’t trigger it to flicker with an alternate cubemap. Also when idle, it uses the cubemap but doesn’t reflect the time of day or change in lighting.) and the cubemap when the player moves the camera.
Its as if is accidentally creating a new cubemap instead of updating/modifying the current ones.
EDIT: I want to clarify that happens in-game (PIE) and not in the editor.