There is a lone leader in a hex with an AFV unit. Perhaps multiple AFVs and/or leaders, doesn't matter. The leader(s) are on the ground, not riding the AFVs. An artillery strike occurs with an X result.
Rule 6.71 says, "If one or more leaders are in a hex with no other units, one leader is eliminated per step loss scored on the hex by bombardment or direct fire." Is the leader eliminated by the X?
The implication of the rule is that other units in the hex with a leader take casualties, and the leader might be hit,
rule 6.7, but AFVs are immune to such casualties. If the leader isn't eliminated, that would make walking around with some rinky-dink tankette really good protection.
This issue isn't one of mine, but brought up by another trouble maker.