Let me guess, you removed SFF_CLASS from the Release group and entered RS_FOR_3021_PR instead.
Or you even deleted all Release groups and created a new P1.
This is what I meant with deleting the header without deleting the child segments.
Use CL20N and deleted the SFF_CLASS for each combination of release group and release strategy (that is listed with a red dot in the analysis) and add the new defined class RS_FOR_3021_PR