I came across one, and then did a search to find the other 3.
The following 4 units have both the CASE and ENE specials on their Alpha Strike cards. I believe they should be mutually exculsive:
Strider SR1-OM - No ammo that I can see, so should probably just have ENE.
Catapult CPLT-C6 - Qualifies for both CASE and ENE, but CASE is superfluous (or confusing) rules-wise.
Hephaestus Scout Tank D - Has AP Gauss, which I think is explosive, so should have CASE but not ENE.
Demon Tank (PPC) - No ammo that I can see, so should probably just have ENE.