Incredible inconsistent ironing?

Hey guys, so I'm still fairly new to 3D printing, but I alredy have quite a few successful prints under my belt, so I'm not a complete beginner. Among these were several of these "molle name tags". Pretty much just a flat piece of plastic with hooks so they fit on molle. Pretty useful for putting your name on stuff that has no velcro patches. Having made a few for myself, I agreed to make some for our whole team. (They have names on them, hence the pixelation)

Herse the issue: the ironing is very inconsistent. I made these successfully a few weeks ago (3-4 at a time). Before this batch i made a full ironing test, did a test piece with the best looking ironing settings and it looked really good. So i go and do the wohle batch (about 2/3 of the build plate full) and this. Some like the second photo look okay and some look really bad. In the first pic there are some pretty big inconsistencies even on the same piece. The bottom looks good but on the top it's really underextruded. Theres also no reall pattern to this, like bad towards the edge of the plate or so, just randomly bad patches.

This was printed on the a1 combo, standard 0.4 nozzle , 0.2 Layer height. Ironing settings as usual but speed set to 25 mm/s and 20 % flow. Filament is bambulab pla matte

How does this happen? How can i fix it?