When the dialogue for radio support initiates, if your character spots an enemy AI he will callout to his team the enemy's location, which stops the radio support dialogue already in progress. The radio support dialogue must then restart from the beginning. This happens with automatic callouts disabled in menu. If you're surrounded and trying to call in arty support, the dialogue will be interrupted multiple times. I've tried blocking my character's view with cover, but even this doesn't always work. This makes the feature of radio support frustrating to use.