Hello,
I know this is kinda old, but... did you find why it happend?
In my case the attack was stopped even faster. No matter what I hit (mob, npc, player).
But after like 20 hours is went back to normal.... By itself...
I think it is related to Oly because in same time it went back to normal Oly fighters gain like -4382763637328 or +87363637838477337 points ;/