When I try to create a GUI attached to a block, and have it (the GUI) display an NBT tag (with <BNBT:number:tagName>) or the position (with the "This block is located at <x> <y> and <z>.") it just displays 0 (or 0.0 for number tag) for everything. I don't think I did anything wrong myself, it doesn't seem like it at least. I've attached the workspace I've made to show the issue.
EDIT: It seems this bug doesn't happen when you're using a GUI with inventory. GUIs without the inventory, however, will still not work.