As you're aware MD has been a clusterf**k this year.  ProSeries was one of the first to finalize the new 510/511 and they actually did a better job than other softwares even better than Lacerte which is still having errors.  But, in my opinion things like diagnostics and other messages are secondary and may have not been updated.  As long as YOU are confident the forms are correct then ignore the diagnostics.  If you are still concerned, contact ProSeries with the specific item and see what their response is.  So far I've been pleased with the new 510/511 forms.