護照上加注 is mostly used in determining continuouse

residence. Citizenship interview office will defaultly consider the continuos residence be broken if such an annotation is here.
Revoking GC for leaving over half year is very rare. I know a case in which, seven years in a row, a German Lady came back once a year for a short stay of a couple of months. Her GC was revoked at the eighth trip. She had chance to contest but did not.