After insertion of the time and committing, the time switches one hour earlier in the admin view. Interestingly the public display is correct.
When committing a second time without any correction, the time is set to the 'new' value i.e. one hour earlier.
The timezone of my server is UTC+1, this is set in WordPress and in the user profile. The server is running as multi-user site, but activated only on one site.
This happens in 1.9.1 standard as well as 1.9.2 standard. There is no issue in 1.9 versions.