Okay so this is my current dilemma. I suspect it has something to do with a cube size limit on CPM, been looking through the code to find a way to remove this limit to no avail. Please fix.
playermodelnedlehaver.zip

Here are both the cpmproject and the cpmmodel. Tested on 1.18.2 forge and 1.19 fabric with the same results.

CPM has a limit of 25 on cube sizes. You have to split up the cubes in Blockbench.