Gargo i find I'm immune to bombs sometimes but that's usually just after waking up from being knocked out from a bomb. I figured there's some sort of cool down. Is this what you experienced?
Occasionally I'll be immune if I'm grabbing the floor and maybe up againts the wall. I just figured the blast radius isn't a sharp horizontal and might be angled up slightly.
Either way, I'm not sure if a client (person who has the game) can mod their game to have stun/knockout immunity. Theres server mods, which is what youll see in some Minecraft servers. They have to mod the server itself. Then there's client mods. Thats like x ray vision in Minecraft. You cannot add other crazy mods and join someone's server. Thats just not how client side works I don't think unless there's some very strange, unique exploit.
Join the mob of people who dislike and critique the physics of this game. I think thats the more accurate and credible direction to point your finger.
Hope your day is going good so far!