The latest patch also came with the implementation of the latest Historic banned and restricted announcement, and players who had Nexus of Fate, Winota, Joiner of Forces and Burning-Tree Emissary in their collection would have received Wildcard refunds for these cards today. Wildcard refunds for Nexus of Fate had already been issued last year when it was first banned for best-of-one play, but a bug in the client caused players to receive these refunds for the second time.
Likewise, refunds for the suspension of Burning-Tree Emissary was also given out, which is not supposed to happen until it moves to the permanent banlist. MTG Arena is not reversing these errors and allowing players to keep the Wildcards. Please see the official statement below.
NEXUS OF FATE
Nexus of Fate wandered into a new Banned and Restricted announcement and back in time. True to form, it it allowed you to receive an extra Wildcard grant (as opposed to an extra turn).
. . . We hope you appreciate the irony as much as we do.
Simply put, players who had previously received a Wildcard grant for Nexus of Fate when it was banned in best-of-one Standard found themselves receiving an additional grant this morning when the Historic ban was implemented. This is a bug, and should not be expected when a card ends up banned in multiple formats at separate times. Players will only receive Wildcards once for each Standard and/or Historic banned card in their collection. If you gain additional cards in-between bans in those formats, any subsequent grants should only cover the difference.
Collection error in your favor, we will not be putting these Nexus of Fate-turned-Wildcards into the graveyard. Players who received them will find them shuffled into their wildcard pool instead.
Speaking of adding things to your wildcard pool, Burning-Tree Emissary granted uncommon Wildcards when it entered our Historic Suspension list. Again, this was a bug, and is not typical nor expected when a card is suspended. Players should only expect to receive a Wildcard grant when a card is fully banned.
Unlike the mana pool, you don’t lose unspent Wildcards as steps and phases (or scheduled maintenance) ends. Players who received these unintended Wildcards will be able to keep them, and use their subtle powers when crafting.
Source: JUL 16 – Wildcard Grants