Eric,
We’ve been able to reproduce this at our end. However, this is an issue in the PHP dev tooling and not in MyEclipse as this validation functionality is provided by the PHP tooling. Additionally, we were able to see the same errors even when we tried PDT 8.3 installed in the latest Eclipse release.
I tried looking for an open issue in the PDT issues list here https://github.com/eclipse-pdt/pdt/issues but could not find one (may have missed it). Perhaps you could take a look and open an issue there?