Error opening file with association (double-click) when there are Unicode characters in path

I am using GP v.3.2.3247 under Windows 11X64 Home edition.

The .gan files are associated with GP and clicking them will start the program. However the file does not load, instead GP displays an error message. This only happens with files that contain national (Greek) unicode characters in the filename and/or pathname. The same file if re-named in English and in a folder structure without unicode chars, works: opens the program AND loads the file
The following is the exact error message:

Something went wrong

Failed to parse document
Unable to open the file: D:\pCloud Sync\�έα ��γα\1049 (Gerstel.Βου�κά�ι)\1049K-2022\ProjectManagent\InitialGeneralGantt.gan (The system cannot find the path specified)

Once the program is open, there are no problems loading files with unicode or saving them.