A TIME TRAVEL SYSTEM - TO THE PAST AND PRESENT.

I should have clarified.

I referenced the ultimate items because those are the most common designs I've encountered but trademark items can be just as bad. (Plot-wise not gameplay-wise)

For example in your scenario, you explained the justification of gaining the item but you didn't explain the justification of switching from that item.

Let's say a player does get that exclusive item but then later in the game, the item's power just loses out against a generic item (this is why people tend to make ultimate weapons as the rewards) then the question for someone who's immersion is just as important as gameplay is whether they can make the bard keep using this item or they will be forced to grind like crazy just to maintain some semblance that the soothing memory is still valuable to that bard.

This isn't always logical or rational either. Sometimes players may even want a modified ending for keeping those items and, design-wise, now you have a lot of extra conditional events to add on top of the time travel.

Again this is only if you really want to deliver the design. Not many players would demand or overthink these things through. It's just as far as ideas and narratives, that's one of the pitfalls that lead to a poorer story. Doesn't mean bad, just poorer or executed greatly...the more apt term would be less memorable. You really have to have experienced comparable great scenes though to even get to this type of criticism and many players simply don't have that expectation or standard but still, it is a notable enough warning methinks.