Strange Behaviour of Meter Changes after XML Import (SOLVED)

Hello together. After importing XML I got a real strange behavior of my Time Signatures. I cant change the Time Signature anymore. I tried to change 6/8 to 3/2 it only happens on one stave. The others keep the old Meter. I tried to experiment with Local or Global, but could not change anything to the better. Any Suggestions?
Question Meter Change.dorico (913.8 KB)

The time signatures are all independent.

To convert them…
Use the System Track (alt-T) to select everything.
Filter for Time Signatures.
Delete them all
Replace the time signatures (shift-M …)