Strange one today.
MDT integrated Task Sequence, version 8443, running in ConfigMgr (1610) kept creating a BDEDrive with an assigned drive letter when building a device using legacy BIOS.
I’d ticked the usual checkbox in the BDEDrive Partition properties, ‘Do not assign a drive letter to this partition’ but a drive letter was assigned with every build.
The fix was to untick the box!
Not seen this behaviour before. I would love to know if others have experienced this. Let me know if you have.