I’ve run into boot camp impacts at the same point. To jump to the point, it was due to the OS/X system preferences boot drive not being set to OS/X before running the boot camp utility - creates the bootcamp partition.
When I set OS/X to be the selected boot device first and repeated the bootcamp process, bootcamp was successfully able to turn the boot bits FROM OSX to Bootcamp.
The boot camp utility fails when it has no target to move from. It fails silently, no error alert, no log message, no joy. It’s simple as a missed requirement in the bootcamp utility that it set or validate OS/X is set to boot before it try’s to change it. (and fails)
Also be sure to select the EFI windows boot over the non EFI option.
Hope this helps.