Solution: After a debugging and I found this 2 oss-notes:
2928354 - The provided key fields are not supported by the condition type XXX
2992615 - Migration of fields not listed in Supported Key Combinations in S4Hana On-Premise System
Then I added with SM30 in view VCND_MIG_SAPFLDS a row for the fieldname WGLIF (or LIFNR,....).
And also you need to add I also need registers for field KFRST in any case in the staging case for Conditions Keys.