More cover art weirdness

Having owned a Vault2i for several years now I've learned to live with some of it's peculiarities but this is a new one.  After ripping a bunch of CD's the cover art was from 2 or 3 albums.  I added the cover art via mp3tag and reindexed without success.  I also rebuilt the index, also without success. The cover art was not displaying.  I access the vault through both the windows and ipad/iphone BluOS app.  I then upgraded the BluOS windows app.  I'm up to date with the IOS app but did remove the app cache on both my iPhone and iPad.  Now the 'missing' cover art appears on the Windows app but the same cover art doesn't display in IOS.  Very odd.

What would cause BluOS to display cover art when using the Windows app but the same cover art is not displayed when using the IOS app?