Cross references disappear

I have some relays on a page.  The cross references for the NO and NC contacts had been working, then I noticed some (not all) were blank/missing.  I did Manage-Update Page and the cross references filled in as expected.  I saved the page, left the page and later came back, the same cross references were missing again.  This time I tried Manage-Refresh Page and again the cross references appeared correctly.  Saving the page and closing the page, then returning, they disappeared again.  It's always the same cross references that disappear.

Of course when publishing the drawing set to PDF, when the page is opened for processing, the cross references are missing.

I did a Modify Page on this page and the pages the cross references point to, to make sure all the pages are set online.  Same result though.  I did a Rebuild Project Database, no change.

Any other thoughts?