Null instance in Inventory

[Pham_Tuan_Anh]

In the course there is an error display:

When i follow steps in the course and run the error message repeat multiple times and i couldn’t figure out why. But it seems like the error fixed in the project on github when i pull code as a whole(master branch). Can someone explain me what cause the problem?

[Pham_Tuan_Anh]

I found the problem. Apparently i forgot to remove the pumpkin representing health pickup and my mouse was hover over it.