Considering the obscure situations the game has accounted for, I wouldn't be surprised if there was a secret ending to be found here.

The game has been pretty inconsistent about whether time limits matter or not (for better. The Druids will kick the Tieflings out in about however many days it takes Tav to find an alternative solution but Nere will die within 12 hours of Tav stepping foot inside the Ancient Forge. So who knows if this actually matters?)

To Recap:

Wyll's Quest from Mizora in Act 2 is to free one of Zariel's assets from Moonrise Towers. Through Karlach interactions we get a red herring, thinking it's Florreta the Garroter but surprise it's Mizora herself. Passing a check against her when rescuing her, she agrees to free Wyll from his contract. However, that doesn't happen immediately because of Clause Z, Section Thirteen: If the soul-binder consents to separation, she will release the soul-bearer from all obligations within six months.

So here's the obvious question:

What happens if you take 180 Long Rests after Mizora consents to break the pact with Wyll?