Items and one-shots with "On your turn, roll a die..." (Disney Munchkin)
 

There are items like Triton's Crown (a +3 headgear) whose text says:
"On your turn, roll the die. On a 1, go through the Door discards and suffer the effects of the first Curse you find."

When during my turn is this resolved? And would it only apply if I actually use the bonus of the item, i.e. use the item in combat? If it's not my turn but I use the item's bonus, like when I'm a helper to someone else in combat, do I not need to roll the die since it's not my turn?

Then there are several one-shot items with this same text AND a combat strength bonus. For example, the Magic Rose is a +4 bonus whose text is the same as above, plus "Usable only once" at the end. So is this a slightly risky combat bonus with a 1-in-6 chance of a penalty? Note that it doesn't say "play during combat," so I suppose I'd have to play it on myself or another player before kicking down the door in hopes that a monster is encountered? If no monster is fought this turn, does the card's bonus and effect pass without activating, or is the card kept in play until it's used?

I also hadn't considered that any of these might be misprints until I found the following thread. Magic Rose is discussed, but there doesn't seem to be a firm conclusion about whether it's a misprint:
https://forums.sjgames.com/showthread.php?p=2360965

Re: Items and one-shots with "On your turn, roll a die..." (Disney Munchkin)
 

Tritons Crown wants you to roll at the start of your turn.

And yes, I believe Magic Rose and Magic Carpet are misprints.