An upcoming backend update and sensor release will also resolve this. The policy change will need to be requested again after the update as the first switch is being rejected.
What is the risk of deleting the pscrulecheck registry key?
If the sensor has the Enterprise EDR (Formerly CB Threathunter) feature turned on and the sensor doesn't have manifest rules this is not a viable workaround. The sensor will stop sending EDR events if it doesn't have the manifest rules and this key is deleted.
New installations of 3.6 are not effected by this, only upgrades.