Model:Samples: I can not assign Samples to an empty pattern

Hey there,
I can’t assign samples to an empty pattern. Couldn’t find any matching topic so far.
So here is what I do:
I go to an empty pattern (e.g. B07) -> select the desired track -> open the sample assign menu -> select the desired sample by turning the data knob -> I press the date knob to select the sample (it’s highlighted then) -> then I press the WAVE button to exit the sample assign menu.
during the whole selection process I can hear the selected samples but as i exit the sample assign menu the previously selectetd track is still empty.
Assigning samples to an existing pattern is no problem and works as expected.

So here is my workaround:
I copy a pattern from Bank A -> I paste it to any empty pattern on Bank B - F -> I clear all data of this pasted pattern -> then I swap the samples on each track.

This is slightly inconvenient but it works.
Any ideas. did I miss anything?