5.0.b1 / Touch Mappings

[CharlyDL]

I'm trying to map 8 lamps (single channel, frontlight) to 8 faders (TOUCH).
Seems to be easy but it doesn't work correctly.
Up to 4 assignments are sometimes possible, but then at the latest strange reactions occur.
For example instead of creating a new shortcut (TOUCH MAPPINGS) another not selected shortcut is updated. The selected fader does not work with the desired lamp, but with another one. And a previous shortcut is lost.
Another time only one shortcut for this group was possible. All new assingments only changed the existing one.
Is it a bug or am I doing something wrong ?