If you long rest in the Defiled Temple, just before entering the Underdark, the previously opened door closes again, but characters can just walk through it as if it were open.
Glowcap mushroom doesn't have an an image
Sunwalker's Gift - this ring doesn't include a mechanical description of what it does, but looks like it is intended to given the amount of blank space beneath the fluff description.
Eat - unable to do this as a bonus action during combat, despite it saying it's a bonus action on food item info.
Inventory Interaction During Combat - unable to interact with items in inventory (by opening inventory) while in combat. Items must be on hotbar in order to use them.