8 Hotkey error with "untap" Ability on Umbra Mantle
The "Pass if no legal moves" hotkey does not work with Umbra Mantle
1) Summary of the problem: If you engage the "8" hotkey and only have the "untap" ability on Umbra Mantle available, the game passes through combat.
2) Equip Umbra Mantle on a Birds of Paradise with a Zirda in play. Attack with the Birds of Paradise, and have no other activated abilities or spells available. The opponent has a flying blocker and chooses to block.
3) The game passes through combat, not letting you untap the bird and pay the "1" untap cost by tapping the bird.
4) The "untap" cost should be able to be paid by the bird after untapping it, so the untap ability is an available activated ability even though there is no mana available to perform the action, and so the game should NOT auto-pass through combat.
It sounds like you may need some more troubleshooting advice, please submit at: https://mtgo-support.wizards.com/hc/en-us/requests/new and select 'Technical Troubleshooting'.