ID 441695 - Exporting .ptx files is disabled or returns an error in Mari Non-Commercial

Problem summary
Exporting .ptx files is disabled or returns an error in Mari Non-Commercial

Channel/Layer export options are greyed-out and disabled, while attempting to export .ptx from Paint nodes or the Export Manager returns an error.

Customer reported version
Mari 5.0v4

Customer reported platform
Windows 10

Steps to reproduce

1) Launch Mari Non-Commercial (add --nc argument in terminal)

2) Create a PTEX project

3) Right-click a Channel or Layer and check the export options, notice they are greyed-out and can't be clicked:

For Paint nodes:
4) Right-click a Paint node and select Export

5) Set a valid filepath and click Export

For Export Manager

4) Open the Export Manager

5) Add the Ptex Channel as an Export Item if it is not already present

6) Set a valid filepath and click Export

Expected behaviour
Users should be able to export .ptx files

Actual behaviour
Export options are disabled or an error is returned:

Workaround
Unknown.

Reproduced by support
This bug has been reproduced in:
Mari 5.0v4 - Windows 10 - CentOS 7.9
Mari 4.8v1 - Windows 10
Mari 3.1v1 - Windows 10 - CentOS 7.9

Earliest version tested
Mari 3.1v1 - Mari Non-commercial did not exist before this version