I've had to pinch the gap on the olfa light weight blade holders often. They make them with a broad tolerance and that gives the tip a lot of wiggle. A quick pinch with pliers while there's a blade in the knife will correct the flaw and prevent the blade undercutting from shifting.
A lot of cut issues are a combination of the blade angle in your hand, the straight edge being above the surface, the media, and the table surface. Old cutting mats, plywood table tops or plastic table tops get grooves cut into them with time. Those grooves act as channels to mis direct your knife tip.
For accurate cutting rotary knife trimmers are so worth it. They range from $200 to $900 for manual models. Guillotine cutters are best for gang cutting lots of identical sheets.
its only a freaking sign!