My printer started off as an Anet A6. I've switched it to an aluminum extrusion frame, installed a BLTouch, switched everything to 24 V, gave it an ARM controller, etc. Printing runs over Octoprint. Material is ASA at 255 °C with the bed at 95 °C.
After my most recent modification (switching to IGUS plastic bearings and the aforementioned aluminum frame) I'm experiencing a printing error. The vertical holes are skewed diagonally (picture provided). This seems to be almost not visible at 40 mm/s, substantial at 60 mm/s, and crazy at 80 mm/s (I don't print at this speed but just for testing).
Since it is diagonal, I can't think of a source of the problem. The larger geometries don't seem to be affected. Mostly 3 mm screw holes turn out bad.
Any suggestions on where to look for the source of the problem?