Could you please import this registry and test again. This problem seems to be enabling debug prints is giving room for mounting the FlashDisk and that is helping the Unified Multitouch driver to load always. The below registry fix will do waiting for FlashDisk to mount before other drivers to load.
Wait4FlashDisk for installer drivers(fix1):
When ASYNC driver loading is enabled, even though Wait4FlashDisk is set, the UnfdMultiTchDrv will be loaded by another core simultaneously. In order to make UnfdMultiTchDrv depends on Wait4FlashDisk, this fix will be used.
Disable Async driver loading(fix3):
In order to remove asynchronous driver loading feature below registry fix will be used
I guess, I provided enough information to understand these features better and make decision, let me know if you need any help on this.
You need to use either fix1 and fix2 or fix1 and fix3 combination.
Please read below documentation for more information