It happens to me sometimes, too, but I don't think that it's related to the beta because I'm getting this since many macOS versions.
In my case a reboot always fixes it… till next time.
10.13.5, i have same problem.
I turn on the computer, enter the login, transfer the data to the MacBook Air and going to the meeting. My internet operator provides me with a static ip and I previously worked successfully with ARD, but after update to 10.13.5 - I see black screen when connected via Apple Remote Desktop, an additional connection attempt does not lead to success. Apple Remote Desktop doesn't available on the home iMac
Only reboot fixes.
Ohh... many time i tried to post message, but have error message "invalid character", step by step i got invalid word - it is - w i f e without spaces
test - gay