In my 2.10 quest, when I initially collect the letter it shows up in the subscreen just fine. Once I use it to open up the position shop, the letter graphic changes to the tile you see in the screen shot below.
Potions will work just fine though. The graphic in the screen shot will reappear when you use the potions as well so after the shop is set up, the letter item just completely disappears.
Letter graphic bug - build 346
What happens in the NES after you use the letter?
The graphic stays as the letter. It is also the letter when you use up your potions. That is what should be seen.
I've seen this myself and can confirm. What it's doing is using the Letter (used) tile. Much unlike with the standard Letter, the Letter (used) is defaultly set to that ugly thing. If you set the tile for Letter (used) in ZQuest, this will go away, but of course, older quests are broken either way.
Yikes!
Due to a big bug in the item loading code, all of the new items, as well as all of the deprecated quest rules, no longer worked correctly on old quests.
Fixed, I hope. Please test aggressively in the next build.
The letter is automatically fixed in quests saved before the item properties launched; as always, newer quests will need manual fixing. Since the tile is a graphics property, "defaults" won't reset it; you'll need to specifically find the tile you want.
I can confirm this is fixed in build 357.