I had this same issue when I tried to update my bios to 0348. It wasn't a bitlocker issue for me though. If it isn't asking for the recovery key, I'd guess it's not a bitlocker issue. I'd recomend going into the boot menu and re-flashing the bios back to it's previous version. What version are you trying to upgrade from and to? RYBDWi35.86A isn't a BIOS version.
In this particular case that you are not asked for the Bitlocker* Recovery Key, I suggest re-flashing the BIOS on your NUC 5i5RYK rom here Intel® Download Center
Additionally, you may visit Microsoft's * BitLocker Recovery Guide in order to do an advance recovery https://technet.microsoft.com/en-us/library/dn383583.aspx