Do Sebellians have a resistance to Flash Grenades or something?

I started another game of Xenonauts and the first ground mission was a landed UFO (local forces say they downed it, but it's never damaged). It was Sebellians and I managed to get to the UFO with four guys standing, open the doors and find three more Sebellians in there (why there are nine of these giant lizards crammed into these things is beyond me). I toss a Flash Grenade to suppress them and... nothing, two of them get reaction fire and kill one of my guys. So I chuck another flash grenade with a different guy, they are again not suppressed, and they proceed to reaction fire again, killing the remainder of my crew.

The suppression resistance of Sebellians was buffed recently, and Androns can no longer be suppressed.

They have a 0,5 suppression multiplier atm, it is in aiprops.xml. Also you should throw from cover so there is no reaction fire, I usually position my grenade lobber 2 tiles behind the guy that opens the door.

While sebs do take less suppression, what you're describing is a bug: throwing flashbangs into a UFO from the outside can result in the flashbang being a dud. It's most easily seen in lightscouts. I've seen this exact thing happen with caesana non-coms, too, who take normal suppression damage.

You can tell that seb non-coms are meant to be suppressed by a single flashbang because that happens outside the UFO, or if you throw the flashbang from inside the UFO itself.