@mrehorstdmd
At last I understand the differing opinions on core-xy with twisted crossing.
Some say it works well and runs smoth, and others say it grinds the belts rapidly.
Most agree that the belts need to be back to back as they cross.
But here comes the point:
They have to be "back to back" all the way! Your belts have the teeth facing each other at the pulleys.
You do the 180º twist, and avoid that the teeth face each other in the middle. But the result is that
they scratch edge to edge instead (at two points).

With the usual core-xy with twisted crossing layout, you can do it like the image below.
Green circles marks twisted regions. Black lines next to the red/blue lines marks the side with teeth.