propowntag setting on optiplex 790

If I attempt to set the propowntag with cctk (2.0.1 on linux) on an optiplex 790 with a setup-password already set then it rejects it saying: Error in Setting the Value, and returning error 188, e.g. (with the password changed):

# cctk --valsetuppwd=Secret --propowntag=***
propowntag=***

Error in Setting the Value.

but if I clear the password first (with cctk --valsetuppwd=Secret --setuppwd=) it works, and then I can set the password again. Just putting ths here in case the workround was not obvious.

This does not seem to happen on earlier optiplex models I tested, but then the optiplex 790 is not listed as supported by cctk 2.0.1...