False Negative check for DD0028

Dear development team,

It seems like the DD0028 (Term/NCI Code mismatch in Codelist) is not checked when a codelist is NOT extensible.

I happened to find this when I was looking at source codes on Bitbucket (go to the link below and search by "if (!isExtensible)").

https://bitbucket.org/opencdisc/define-generator/src/a8015905b5ebb8a6518dc3bb1c81259a032bc5d5/src/main/java/org/opencdisc/define/validator/ContentValidator.java?at=master&fileviewer=file-view-default

Regards,

-Ebi