Hi Evaristo Cuesta,
Thank you for providing the detailed explanation regarding the reporting issue.
We have reviewed the KB article you provided. In the article itself, we mentioned that filtering and grouping are not recommended with this type of customization. When grouping, we created the sorting description for the respective column, which indirectly suggests not to use sorting with this customization as well.
If you have any other concerns regarding this, please let us know. We are happy to assist you.
Regards,
Sreemon Premkumar M.