Graphical glitch when re-entering game from Daydream Home screen multiple times

Hi, we are currently developing a game for Daydream in UE 4.15 and are experiencing a very strange bug.

The issue occurs when exiting on device (Pixel XL) from one specific map to the daydream home menu (by clicking the home button on the pointer) then re-entering the game a couple of times. Usually every other time you re-enter the game (though it has been observed breaking this order very occasionally) a strange graphical glitch flashes in front of the camera for a couple of seconds before going back to the level:

It looks like a sprite-sheet, and though there do seem to be a couple of our assets bundled in there the rest look like they’re probably unreal editor assets.

Has anyone else seen this or have an inkling as to why this is happening or how to fix it?