x265 Encoding Issue with MP4Box

[Selur]

Argh,..
I see the problem:

"D:\Data\Documents\Program Portables\Multimedia\Hybrid\64bit\MP4Box.exe" -add "C:\Users\Admin\AppData\Local\Temp\SOURCE~1.264"#video:fps=29.97:name=:lang=und"en" -brand avc1 -add "C:\Users\Admin\AppData\Local\Temp\IID_3_~2.AAC"#audio:name="""en":lang=en -mpeg4 -itags tool="Hybrid 2019.11.03.1" -tmp "C:\Users\Admin\AppData\Local\Temp" -new "C:\Users\Admin\Desktop\19_35_13_1010__03.mp4"

there are a few things wrong with this call.
Seems like there is some issue with the adding of the language tags.
-> do you have a small sample of one of you input files so I can try to reproduce the issue?