I'm playing on a standard Creative world without any texture packs, behavior packs, or mods. Usually, if I'd want to clear my hotbar I'd open my inventory and press X and it would clear. To see the bug you just have to: 

1. Open the Creative menu. 
2. Fill your hotbar. 
3. Attempt to clear by pressing X or whatever button/key is bound to "Crafting". 

        What happens is you either take half or the "Select Recipe" button takes the "Clear" buttons place and does nothing. 

        What should happen is your hotbar clears when you press the button mapped to "Crafting".