Magenta tint is gone after cleaning?

Something really weird happened to my QD Oled after cleaning a smudge on the bottom right corner. First I used a destilated water with microfibre but it didn’t help to remove the smudge. After that I’ve used whoosh! and the smudge was still there but the magenta tint was gone in that area. It was only noticeable from certain angle. At this point I’ve stopped cleaning this area.

Next day I tried different microfibre cloths with destilated water and I managed to get rid of the smudge, looking good but still no magenta tint in that spot. It’s not noticeable as before and visible only from certain angle when monitor is off.

I’m just wondering what exactly happened???

Any ideas?