After enabling FileVault on guest, when booting, FileVault "logon" screen does not show mouse movement. Must use arrow keys to choose the user account and then "return" to enter password. Mouse cursor does not move.
This was not a problem prior to Mojave.
Downgrading the virtual hardware version from 16 (the most recent) to 14 (the prior available) is a successful work-around, but not a solution.