Matura value in PER_HIGHEST_EDUCATION_LEVEL common lookup cannot be added

Summary:

I am trying to add Matura value on the PER_HIGHEST_EDUCATION_LEVEL common lookup but I am having this error. I double-checked this lookup and there is no value or code like this but still having this error. Are you experiencing the same?

I tried to have the value in all capslock and it works no error occur. But it is not a standard format for this look-up.

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