Who I have the same questioned this topic

After receiving  latest update (NCL 25.86-11.4) Bluetooth disable and I could not enable it - trying to switch ON and it drops back to OFF.

Reboot, Factory Reset, reinstalling update though Verizon Setup Assistant - nothing helps. Looking started process I found that when I tick switch to ON - Bluetooth sharing process started and Bluetooth Gatt  started - but no other Bluetooth process (e.g. PanService, BTPbapService, HidService, Headset Service etc.) has been started. It more looks like software problem. But since there is no option to roll back to previous version I have to wait for the next update. Or there are other possible options ?