There is the "This item will stop working after Crimbo 2019" issue. I think a bizarre and unnecessary mechanic, but, here we are. Or here we will be. Just as we were during Crimbo 2015 which had two combat items which have subsequently stopped working. Supposedly.
What dose it mean in 2019, where there are many more items so-labelled?
Guess:
At some point, all items that are so-labelled will have their modifiers disabled.
Food will remain food.
Booze will remain booze
Potions will be usable, but useless
Combat items will be usable in combat, but useless
Equipment will remain equipment, with a particular power, but otherwise uninteresting.
Concoctions will continue to work; ingredients will still be usable, although the result may or may not, depending on whether it is tagged.
I wish I could be sure of that last one. It'd be super annoying if you couldn't make the chefstaff except during Crimbo because the extra ingredients you need to supply to Roderick "stopped working".