[2019] The 10% damage reduction is currently bugged and basically does nothing.

I am not sure if Respawn is aware, I have seen some comments here and there mentioning it but never seen a post about it.

The 10% damage reduction is bugged. Whenever you are full shield and take damage, you can see that little bits of your HP (not shield) is taken away. Essentially, if you fight someone and kill them while having 50% left, you can still see that you are missing health, and will be able to serynge right after which makes no sense.

I used to play Caustic a lot when the game came out, but stopped playing him to try other characters with season 1. When I saw the buffs, I was super excited and thought I could go back to playing Caustic and enjoy him again. However, it seems that the 10% damage reduction buff is just a placebo, as it seems the 10% damage that should be negated, goes to your HP instead of your shield. So essentially, there is no damage negation. I don't have video footage of my gameplay as I don't record it, but I've seen other posts where you can clearly see what I'm talking about. It works for Caustic and Gibraltar.

I hope this gets fixed soon !