If the letter to meet at the crossroads occurs on the same day the tailor asks for the cure, it'll be stuck on an infinite loop between the tailor appearing asking for help and the crossroads letter dialogue.
Edit: I'm guessing the fix for this is to have a conditional check after the crossroads letter dialogue for the current weeks remaining (to see if it's time for the tailor cure quest), and defer the scene transition until after tailor finishes asking for help (a conditional check on that dialogue to see if the crossroad's scene is active - may need to set an additional boolean variable to track this in this situation). Maybe just add a little extra bit of dialogue after that exchange indicating something like "ok, better go to this meeting". Alternatively, maybe have it simply postpone the crossroad's letter event until after the tailor cure quest week.