Steps to reproduce: 

1. create a world with cheats.
2. open CMD and run -> give @p structure_block
3. place the structure block on the ground.
4. place some blocks inside of structure block area.
5. click on the structure block to open the structure_block GUI.
6. click the "?" button(bottom-right) to open "How to play" GUI.
7. result: the 3D model image will vanish WITH_EFFECTS when clicking "?" (step 6).
8. click "back" button, just once, do not exit the structure_block GUI.
9. click the "?" button again.

Observed results: 

The 3D model image will not vanish during transitions of two GUIs, its just shifted to the left.

Clicking more than once the "?" button without exiting the structure_block GUI the 3D model will vanish with NO_EFFECTS.