Tahm E bug

I played a game of tahm kench in normals and in the middle of fights my grey health would start decaying into real health however before this patch it wouldn't decay in fights and to prove they didn't do this to his E here is the patch. Here the is patch E - Thick Skin DAMAGE TO GREY HEALTH CONVERSION 100% of damage taken ⇒ 70/75/80/85/90% of damage taken GREY HEALTH TO HEALING CONVERSION 20/26/32/38/44% ⇒ 25/30/35/40/45% SHIELD DURATION 6 seconds ⇒ 3 seconds COOLDOWN 16/15/14/13/12 seconds ⇒ 6 seconds NEWLESS THICC Shield no longer decays over the duration