I had this problem (once again) today.

I was trying to queue for a Garrosh grp and out of the 10 that were listed 6 was unavailable due to "raid lockout conflict". One of the grps was even hosted by a player that I had been in a grp with moments earlier (although he was not the leader of the previous grp).

I cant provide much insight into the configurations and raid-locks of the hosting players, but i noted that they were all listed as 10-man normal. My raidlock was such that i had done SOO HC bosses 1-3 and then continued on up to Garrosh on normal with various grps (Sha, Galakras, Juggernaut and Malkorok was skipped).

Could it have something to do with the hosting players also having done Heroics and our raid-locks therefore gets listed as incompatible?

In any case, I would have to agree with what one of the earlier posters said. In its current state this feature is more of a hindrance than a helper. Could it not be changed into a warning/notice for RL and queuer instead of stopping players from queueing?

I would also like to thank you for your efforts on this great add-on. For me, on a low-pop realm, its a life saver.

Cheers.