This worked for me. You have to do Steps 8 and 9.
I've got two remote macs both on Mojave 10.14 where I can not use the host keyboard / mouse to control the remotes. Host is also 10.14 Mojave. I've uninstalled the remote agent, rebooted, and reinstalled and granted all of the recommended permissions, with no success. I hope there is a fix soon.
Customer support service by UserEcho