Previously (in snapshot 17w48a), when using custom recipes in datapacks, you could give yourself that recipe using "/recipe give @p *" and you could navigate to your custom recipe in the crafting book. This is no longer the case. The recipes work but do not show up in the crafting handbook. The video below shows the issue. I made a crafting recipe for a saddle and am clearly able to craft it with the materials in my inventory, but it does not show up in the crafting handbook.
What I expected to happen was...:
➕ Giving myself all the recipes
➕ Seeing my custom recipe in the handbook
What actually happened was...:
➖ Giving myself all the recipes
➖ Not seeing my custom recipe in my handbook
Works fine for me. Can you attach your data pack or recipe here?