When you untap a mana-producing creature as part of cost to activate an ability, MTGO wrongly allows you to tap that creature for mana in the middle of paying the cost

[stash86]

What is the expected behaviour of the card?

• Comprehensive Rule 601.2g specifically set the limit on when a mana ability can be activated, which is before we pay any cost. Once we start paying a cost, no more mana abilities can be activated (because we are already on phase 601.2h)

601.2g If the total cost includes a mana payment, the player then has a chance to activate mana abilities (see rule 605, “Mana Abilities”). Mana abilities must be activated before costs are paid.

What is the actual behaviour of the card?

• In the middle of paying the cost (in the middle of 601.2h), MTGO allows us to activate mana abilities, which means it ignores the limit set by 601.2g

Screenshot


(note how llanowar elves can tap during the payment)
Please provide a list of affected cards
Affects: [Umbral Mantle]
See Also: [Rofellos, Llanowar Emissary], [Llanowar Tribe], [Elvish Aberration]

Card Images

[datrobino]

still bugged

[PennyDreadfulBot]

Still bugged according to BOT_Chris in match 247050112.