Hey Carina,
I think it has something to do with how you provide the input. It needs to match the given input list.
Bottom is a comparison of two given inputs if you provide a panel with the same text it won’t list the indice. If you take the item using a list item it will provide the indice.
It seems to me that the list-indice block just doesn’t work consisntently in finding a specified key in a list. If I i.e. copy paste the bottom panel it won’t be able to find it → thus outputting -1 (as stated when you hover the output i)