Expedition mob modifiers

I have run into some instances where the mobs are invulnerable.

How do I check what modifiers are affecting them?

I play on PC.

When you set the explosives you need to read whats written on the boxes
Some boxes say "immune to fire damage" ...immune to lightning damage etc etc etc

You probably blew one of those up and its immune to your damage type, this will last for all mosters that spawn after it too

Also some boxes say "monsters replace 15% of life every 4 seconds" etc etc

Need to read whats written on the boxes