You Edit either the Group or, individual transactions to Change their Schedule, to change them from/to Automatic, etc. This is not changing the Transaction; it's changing what the Memorized Transaction List is supposed to do about it. If you have something that is Not to be created, in a Group, Edit that One and Remove the checkmark to remove it from the Group. Don't leave it in the Group and intend to Not have that Group Thing happen to it.

Changing to Manual, but leaving a Historic Date, means you still get a Pop up. One is Reminder and the Automatic = Permission pop up. Different Pop ups.