What could cause this?

A newly built K8200 makes this kind of mess (se Pictures on link below)when trying to print on exact settings from manual.
.25 mm measured in each corner before print.
The print seems to move the y axis as it moves the second eclipse of the second row of eclipses , it starts there and the gradually adds to the y axis (when Printing the first object, the case for the velleman k8200)


You could try turning the reference voltage up to 0.55 instead of 0.425

This seems to have fixed the offset problem, however it still “blobs” and the nozzle now moves some of the printed material (probably because of the excess material) so the first layers get moved and Printing cant be continued.
Also, the extruder extracts a Little material when hot even when not moving.

Try adjusting the height of the Z-axis manually when you start the print. You can rotate the rod by hand after it has homed all axis and starts printing the skirt. It looks like it’s printing a little bit to high? I tend to let the extruder “press” the filament a little down into the heated bed (you can see it on the shape of the result) and then move it maybe half a rotation of the Z-rod back up.

You could try to recalibrate the Z axis.
Heat the bed to 50C -60C
Find the highest part of the bed.
Take a sheet of printer paper fold it in half.
Set the Z end stop so in drags just a little between the nozzle and the bed.
Move the bed around to make sure it does not drag on any other part of the bed.
If you are using PLA set the extruder temp around 185 and 190C
Make sure the bed is clean before every print I use alcohol to clean mine.

As you go along you will find more adjustments and other parts to make better prints.
Check the link below.
But this should get you started