The trunk has 2 different settings that control recording. Open the Media section under External Trunk Configuration. The Line Recording button allows you to enable/disable recording. There is also a Consent Required button. This requires the customer to give their OK to be recorded before the recording will be started.
Line Recording enabled + Consent Required disabled = all calls will be recorded
Line Recording enabled + Consent Required enabled = calls will only be recorded if the customer says it's ok, i.e. the Enable Participant Recording action is executed in the call flow.
Line Recording disabled = no calls will be recorded, regardless of whether the call flow uses the Enable Participant Recording action.