Something with XTEXT validation

[fontysjeffrey]

We are in the process of intergrating Lemma in our Research Solution Toolkit, but we are running into an error, we are not able to solve and has something to do with XTEXT. The message is :

[main] ERROR xt.validation.ResourceValidatorImpl - The string resource '_UI_DiagnosticRoot_diagnostic' could not be located

I already located this setting, in the plugins.properties, but it does not seem to resolve the value from it.

Any ideas?