I've considered this game to be a spiritual successor to 'Communal Cauldron', a game I made a year ago for the same gamejam. The main inspiration for that game t was actually Soul Builder, which is the same kind of 'drag item into slot to create item' game that this is.
I believe the item dragging not lining up happens whenever the player is playing in a zoomed in browser. I never had time to test it during the game jam because I only tested it in Unity instead of uploading it to the webpage. If I ever update this game, I'll be sure to fix it.