Warmog's unique passive at EXACTLY 3000 hp
[GAMEPLAY] Warmog's Armor passive doesn't activate when I have exactly 3k HP
Played an ARAM with some friends one night and bought Warmog's Armor as part of my set. Being Shen and really tanky (as I didn't care if I took a lot of damage), I went ahead and bought it to boost my health regen. After buying it, I noticed I had 2950 HP (I had a Ruby Crystal and upgraded it to Kindlegem for that extra 50 hp). Got into a teamfight near our inhibitor and waited for the passive to proc. It never did until after I died and bought more HP items.
This is currently the only instance where it didn't activate. I haven't tested this in Summoner's Rift.