Yes algorithms modify your screenshots, as they modifie your photos; and they begun to do that before ChatGPT. Then you save your screenshot; it's generally in PNG which is not a bad format, but still it's a compressed format which can be lossless, but generally isn't as it is applied. Then you crop your screenshot using a shitty android app, which will reduce again the quality.

If you didn't observe that, I'm concerned for you and your lack of observation.