Hi MichaelRensing , thanks for your report and I'm sorry to hear about this.
Right away, does it make a difference if you simply change the image file type or name itself before exporting your screenshot? For example, does saving the screenshot as a .jpg file (instead of .png), named "screenshot" or some other simple name make any difference? Perhaps once you change the directory to somewhere else like your Desktop or Pictures location in Windows for example this behavior get resolved?
Yet another alternative to try would be activating "Automatic Naming" and setting your "Default folder" to any directory you have full access to (read/write permissions):
Otherwise if trying the above does not help with this behavior what so ever please also submit a feedback report including log files and ideally let me know once sent in so that I can have a look right away.
Thank you very much in advance!