Gunner won't engage assigned target

[Rangoon]

Maybe the target was already destroyed, but it was still showing up as a target on both the compass (top of screen) and the white dot indication, with no smoke or other visible damage. As commander in M60, I assigned target, ranged, had Fire At Will order active, SABOT round loaded and indexed. Gunner had the barrel aimed straight at the target, but wouldn't fire. I switched to the gunner's seat, fired the gun on target and had a verbal "Hit" response from my crew. Am missing a cue here?

[Flashburn]

Its possible the entire crew of that tank was dead.  Somehow the AI knows and us players do not.  We will blast away until the thing burns, the ai do not.