Nighthawk R8500 - Cannot rename device

I have roughly 40 devices attached to my router.  I have been able to rename all my attached devices but starting at about device 38 or so, I have been unable to rename new devices.  I can rename devices I had already re-named but no new devices.  I noticed the the UI looks radically different than devices I had previously named.  When I attempt to rename a new device, the fields right justified and the UI doesnt show the Mac address or IP whereas devices I had previously named the fields are left justified and show all the fields including the device IP and Mac address. 

I am running the latest firmware version v 1.0.2.130.

I have no interest in performing a factory reset.  I did reload the firmware, rebooted etc but no change.  This is troublesome as I want to know exactly what devices I have authorized to attached.  I also have a range extender and some devices float betweem the routers and show up with different Mac addresses and therefore show up as a new device - very challenging to keep track of.  

I have noteed others have had similiar issues on other devices and appears the fix is a firmware update.  

Anyone having a similiar issue and is it possibly related to the number of devices attached and renamed? The R8500 can handle 96 devices so I have not hit any physical limitations. 

Thanks!