No confirmed fix yet. Players suggest: Not every day you've got the right challenges, but you can try taking them at night when you've already seen who's sitting down.
Suggested fix (unconfirmed): Water the guards using the bottomless flask or a blue potion purchased from the alchemist. Do not gift the syrup; give it to the Plant Princess during a shift and visit her during the daytime afterward.
Suggested fix (unconfirmed): Let the dragon princess burn your tavern in the beginning, avoid fixing or paying her, and buy upgrades and items instead. Make some synergies, like the sangria one.