Error compiling a custom package for Client Modules

I created a custom package working in file system mode on my PC.

The package is set to be "Compiled into a separate assembly".

When I compile it (selecting "Compile" in the dropdown menu near the package name and selecting "Compile all" in the Actions button) I see a popup error reporting syntax errors in all the Client modules of the package (see image below).

Creatio shouldn't compile Client modules since they are Javascript and not C# (the errors are syntax errors related to C# language).

I also "Generate for all schemas".. I tried almost everything without success.

The package works fine, even exported and installed in cloud production environment, but I cannot compile it in my development environment.

Why does Creatio try to compile in C# the Client modules?