The patch from bugzilla ticket 21174 helped to support sparse OSTs indexes by skipping holes in lov->lov_tgts[i].
However, it is still not sufficient for permanently deactivated OSTs which have lov_tgts[i]->ltd_active = 0 and imp->imp_deactive = 1.
Checking for lov->lov_tgts[i]->ltd_activate should do the trick. A new regression test would also be welcomed.