I tried it again, I think it might be a targeting issue. Last time when I attacked the wrong tank with my last GBU. Could it be possible that that tank was the target for the re-attack? My assumption is based on the radio calls:
1. Loki asks Devil22 to attack
2. Loki calls "good Hits" after the attack and tasks Devil22 to re-attack an instantly states again "Good Hits"
3. Devil22 complys then to re-attack (but never executes
When the mission executed correctly, I deliberately attack the wrong target (this time the BMP and not a tank) and it worked flawlessly