Hanging Key note while Gliding over black key notes


I have this problem that when gliding heavily on the black key notes, on some reason key note sound keeps hanging. While pushing other presets en hit any keynote it is still there with a hanging note/sound.
solution is to turn it on an off. But this I can not do while playing on stage. The Super 6 is connected with only L/R output Jack/Jack.

Also I tried to put a separate midi keyboard on de super 6 and started gliding like crazy and the keynotes where not started to hang.
So that means there is something wrong with settings of failure of the klavier connection to the module

Any body have experience this or maybe know the solution ?

Please let me know