One side of my prints are awful

[analogknight]

Now that I have a proper moment to follow up on my progress. Thanks to everyone that pu in their knowledge on this. After much tinkering, and measuring, and calibrating, I can get decent results. The initial measurements for several of my parts were off, some significantly, and correcying these in Marlin went a long way towards fixing the previous issue. I also lowered the extrusion multiplier from 1 to .75, you can see the improvements in the filament guides. Small prints seem to work exactly as expected. Larger prints have developed an issue where a layer, or 2, will randomly shift along the x axis, usually in the positive direction, although a couple have shifted to the negative.

Could this be a slipping belt? I had an issue with that tower, but the belt tension seems ok. I had assumed if it were stepper related the misaligned layers would be consistent, whereas this is nearly random.