Explosives Expert #2 Challenge only counts frag grenades

I might add that since the 3rd Explosives Expert Challenge is described as:

"Get kills in a match using explosives." [30 required]

... I would also be concerned that only frag grenades count for that, too.
Arguably, getting 30 kills IAR with frag grenades is virtually impossible in any standard game mode (i.e., excluding Portal).