TY for the animation! Hard to say really, does look like something to do with anti-aliasing or similar, but other things that stand out are that it seems only to happen to the green color (the white button in that area doesn't show the effect). I'd still try lowering the threshold as a first point, but would also be interested to see it without bloom and glare and see if those lines are showing variations in thickness and see how the anti-aliasing looks there. The threshold might still be relevant since the green will naturally be less bright than the white.
Sending the scene via private uploader never hurts, someone in the team can take a look and maybe have more ideas and test a few things.
Might also be interesting to know if the New Image Filtering was used (as it takes place across 2 pixels width, rather than the old Tent etc. which only affects one pixel - this might lead to changes in the apparent width or "spill over" from the green into the surrounding area). Sorry, power went out briefly, so I posted previously quickly, but wanted to add this question too.
