I'm using Sophos Mobile Security 8.5.2765 (23) on a Samsung Galaxy S9+ which is running Android 8.0. I've found that if I am on the phone with someone, and an incoming call that will be blocked occurs, the app terminates both the incoming call and the ongoing call.
For example, I have the app configured to block calls from numbers not in my contact list. If such a call comes in while I am on the phone, my call is terminated.
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