Southbound vs Expedition enemy with health regen

So I keep running into Expedition monsters with literally no other affix beside health regen. Unless I take off the Southbound gloves I cannot kill them. What about this health regen tag means I can't freeze them in order to kill them? Seems like a bug to me.

Something like this just makes me wonder how many other things there are in this game that are either bugged or just make absolutely no sense what so ever.

You may want to double check the expedition modifiers by hovering over the icon next to the skillbar to see if one is giving them ailment avoidance.

It may be something shared with other monsters that was being overcome by the mere fact that Frost Blades of Katabasis has built-in damage over time, because while Southbound prevents hits from killing non-frozen enemies, it doesn't prevent damage over time from killing non-frozen enemies.

For enemies without health regeneration, any amount of damage over time will secure the kill. This would mean that even if you couldn't freeze other monsters in the Expedition encounter, you'd only notice the enemies aren't being frozen due to the monsters that can outheal your damage over time.