There is a minor typo in source3/utils/net_afs.c which creates the problem. The patch below fixes it.
Created attachment 5463 [details]
The one line fix
Pushed a slightly different patch at
_() is only for literal strings.
Kai, please check & assign to Karolin if you like it for 3.5.1.
Look good. Karolin, please push.
Pushed to v3-5-test.
Closing out bug report.