When in the "Is in List? Thing List" block I search for a value with equal number characters the answer is always True even if the value searched for is not in the List in question.
Example searching in the List ["1/1","6/1","25/4","1/5","2/6","15/8"] the value 5/5, 6/6, …, 888/888 the answer is always True even if the value is not in the List.
If you leave out the quotes for each item, each item evaluates to 1.
Is 1 in the list?
Maybe you should show us the blocks.
The devil is in the details.
Your list items are in string format but i think you are searching with maths block.
Instead use textinput block and in that give 5/5 or whatelese you want to search..
As said by ABG first shiw us your blocks