Oh for sure, I can imagine.
I think the tough part now, is that if I can't reproduce the issue, it's a bit of a shot in the dark on how I can fix this for you.
My main idea at this point is that it may be GPU related.
When I export the game there is an option to allow blacklisted GPUs, this is the consequence:
"Some systems with poor quality graphics drivers can end up crashing or causing severe display glitches when running games. Browsers provide blacklists to recognise faulty drivers or hardware and fall back to software rendering. This guarantees the game will work, but can result in poor performance on such systems. Disabling this option always uses GPU rendering which can be much faster, but can then run in to issues on systems with poor quality drivers."