So I bought this printer three days ago as a way to dip my toes into the 3d printing world, and it was working great at first. But at some point, the ABL procedure started behaving oddly: Instead of moving down to touch each corner of the printing bed, it's now only doing so for one corner, then moving to the next, but instead of going down, it goes up. It then continues to the third corner, stops, and moves up again. After that, it returns back to home position. The result is that the extruder hovers way above where it's supposed to be --or alternatively bumps into the printing bed when it's near the origin corner-- thinking it's adjusting for some nonexistent slant, dripping filament all over the place.
The gantry itself is totally level, and I can't see any mechanical faults. As far as I can tell, there's no way to manually level the bed, the only option is to use ABL.
I found out that the Monoprice Cadet printer is the exact same one as the Tina2, so if anyone has experience with that printer in particular, it'll apply here too.