What's the oldest live Arena bug that actually breaks the rules?

Here's one from almost a year ago that is still live today.

If you have [[Muldrotha]] out, you should be able to cast a creature from your graveyard once per turn. But if you have a creature with Evoke in your graveyard — such as [[Mulldrifter]] — Arena allows you to repeatedly cast it for its Evoke cost. This shouldn't be allowed, since Evoke doesn't change the timing of when you're allowed to cast a spell.