Some of the Chisel textures are with upper case letters.

• Chisel\assets\chisel\textures\blocks\technical *

I've tried to change them to lower case but my GitHub Desktop seams not to recognize the name changes.
Any idea?
Or someone might be help changing them?

There was a way to force the changes to be seen but I can't remember at the moment (and in transit xD). Alt method would be to purge the entire folder commit then copy back over the fixed naming then commit again.

See this article on the subject: How do I commit case-sensitive only filename changes in Git?

Try this one in a Linux/OSX environment:

https://github.com/Soartex-Modded/Modded-1.12.x/tree/lowercase-chisel/Chisel

Finally I solved this issue.

Thanx for your help.