When used with Curios API (Forge), and when its GUI is opened the recipe book is shown where the Curio GUI button should be.
This doesn't crash the game or cause any harm (you can still get out of Curio GUI), but should still be fixed as it doesn't look very pretty and is most probably not the intended behaviour.

Pretty simple issue. If you need pictures of the issue in game, I could send some here.

Can you post an image please?

Here they are! Sry it took me so long...

Same happens w only the Curios API and this mod. Also, the same happens in survival.

Fixed in v1.3.2.