Here’s the bug report on it:
Please keep conversation about whether or not the amount of life stolen needed to cause the bug should be possible here, and not in the bug report. Please let the bug report remain informative and factual. If you want to complain about how much life and mana the Assassin can steal, keep it here 
The game is still being advertised in this way:
Classic gameplay—the same Diablo II you know and love, preserved.
Great bug discovery and wonderful job in separating the two posts. Also, very good write up, it’s incredibly detailed. I don’t necessarily have a complaint about how much life and mana the Assassin or any other character can steal because in reality the upper bound is always X and Y where X is equal to the max life and Y is equal to the max mana the character has, effectively making the outcome similar to that of a full rejuvenation potion. It’s not like the extra leeched life and mana increase maximum life and/or mana or grant temporary life or mana, the extra life and mana stolen is ultimately just wasted (at worst) or inefficient (at best) stat points and/or gear.
Preserved like a warm gallon of butter milk.
I agree they should fix this by capping Cobra Strike at 30%. Obviously the original dev accidentally added a 0 to the percentages.
they should fix this by raising the limit.
then cobra strike can be rebalanced after