Not sure if you can see from the photo, but the infill doesn’t quite work. There are gaps down the sides of the fill squares.
What causes this? Too hot/cold/fast/slow?
Also could be nozzle size and layer height ratio. Or not enough extrusion.
I just started getting a similar defect (I’ll post some photos shortly). The crazy thing for me is that everything has been working fine for more than a month, and I’ve printed a ton of stuff and made no changes to my setup.
if so, it could be the filament - even if its the same brand, it could be a different batch.
does your slicer have a setting where it is not allowed to cross perimeters while extruding? While there are reasons for such a setting maybe during in-fill it is retracting the filament each time it nears the outer wall?
That could happen if there is moisture in the plastic