Thank you for the detailed report, @it-support@lindner-esskultur.de. I didn’t realize that one could copy and paste from the Windows Snipping Tool into osTicket… very useful (when it works)!
In any event, I did run into the same issue while testing in my demo for vanilla osTicket v1.12.2:
Therefore, this is an osTicket core issue—not an osTicket Awesome issue. Please report it in the osTicket Forum or, better yet, open an issue on GitHub.