/diy/ - Do It Yourself

I have some warping when printing even relatively small parts (this piece was just 6cm across) on my heated bed (60 degrees).
It's always towards the same corner regardless of what part i print.
I'm not sure what to do about this. It's facing a door that's not super well isolated but I don't see that influencing the print because it happened during summer too and ambient inside was cooler than ambient outside.

It's a PCB heated aluminum bed. And just by touch it seems to be heated evenly.
What's the best way to remindy this?