Duplicate type definition error in each rules file

Suddenly every single line of every single .rules file in my code base is marked with the same type of error:

The type EntertainmentRules is already defined in entertainment.rules. (org.eclipse.xtext.xbase.validation.IssueCodes.duplicate_type)

This is the error for entertainment.rules file, errors in other files are similar, just with different filenames.

I know this VS Code extension is not being maintained, but is there a way to disable this check at least?

Thank you!