Based on the descriptions, here is how it should work.
Say K2 has 20000 protection when the match starts. This is his max protection. Assume every enemy hit does 1000 damage.
An enemy shoots him. His MP increases by 1% to 20200, but his protection bar is at 19000 due to the damage.
Another hit. His MP increases another 1% to 20402, but his protection bar is now 18000.
Third hit, MP up to 20606, P is 17000
Fourth hit, MP=20812, P=16000
And so on
But what happens when you pair him with zJyn? K2 almost always counter-attacks and gains taunt when damaged. Taunt triggers zJyn 5% protection regeneration.
MP=20200, ProtRegen=5%*20200=1010, P=20000-1000+1010=20010
MP=20402, PR=1020, P=20030
MP=20606, PR=1030, P=20060
MP=20812, PR=1041, P=20101
etc
K2's protection regen increases every time he gets damaged if he regains Taunt, under zJyn.
Now say zStHan has 20k protection. Every time he gets damaged, he regains 1k protection.
That's how it should work. How it actually works is anybody's guess.