Presence Extension Missing

I have a rather odd problem with my RingCentral Poly VVX 450.
I have added multiple Presence Extensions to my phone and the second one in the list never shows on the screen.
For example, I have added six other extensions to the phone. each users name shows on the list except for the second in the list. If I remove that extension, the next one in the list disappears, and only shows four names. If I leave a blank line, the blank space will show and the next name in the list disapears.

I have tried “resyncing” the phone multiple times, adding and removing extensions but it seems that the second in the list is always missing.