I have had issues with instanceloot (with LookNfeel disabled)before so I always had this module disabled.
However yesterday I found out that with instanceloot on, you could actually click the boss note to see the loot table (this was always bugged for me). However it is not possible to see the tooltips of the item without having to close the map (or enabling lookNfeel with I don't want), it seems that the tooltips do show, but under the map. I would love to see this fixed.
I use KC_Items2 and Mendeeleev. I will try if anything changes if I disable these.
Edit: I disabled all my addons except for all libraries and cartographer+modules this did not solve the issue. The only thing that helps for me is enabling the LookNfeel module, which I dont want because I want my map to be fullscreen with a black background.