It seems to me that you are both using the jQuery German workaround that I came up with here:
https://osticketawesome.com/forums/topic/osticket-1-14-patch-4-german/
This must have something to do with your issues, but I can’t reproduce it on my end.
Please try resetting any Ticket Queue customizations that you have:
If doing that doesn’t resolve the issue, the only way I can help is if I can access your installation to see for myself.
Please submit this form (you can ignore the CPanel, SSH and FTP sections):
https://osticketawesome.com/troubleshooting/assistance-request-form/