FileVault encryption makes wireless mouse and keyboard inoperable
I recently purchased an iMac 21.5" 4K system. I am running macOS Mojave 10.14.3. Everything worked fine until I turned on FileVault encryption. After trying to reboot the system the wireless mouse and keyboard were inoperable. I could not even get to the login screen. Finally, I connected a USB mouse to the iMac and was able to undo the encryption which resulted in the wireless mouse and keyboard working normally again.
Conclusion: there seems to be a bug in the FileVault software.
Has anybody else experienced this problem? How do I make FileVault work on my iMac?
iMac 21.5" 4K, 10.14