@restrict causes a warning when using it is used for minecraft made recipes.

When the definition is:
" Restricts the recipe to everybody.
This is the player-friendly version of @remove because crafter gets a message when trying to craft the recipe."

I wouldn't expect a warning to result.

What is the recipe used and the warning you get?

Recipe:
@restrict This item is banned for balancing reasons!
diamond:0 + air + diamond:0
diamond:0 + diamond:0 + diamond:0
diamond:0 + diamond:0 + diamond:0
= diamond_chestplate:0:1

Warning:

File: diamondban
line 1 Warning: Recipe already created by Minecraft, recipe overwritten!
TIP: You can use @OverRide flag to overwrite the recipe or @remove to just remove it.

That's fine, it'll be a reminder for me to look into it a bit more.

The quick solution is to set "disable-override-warnings" to true in config.yml. There's quite a bit of code that needs to be updated to improve things like this, but they may take some time.

Alright, want me to leave the ticket open in the meantime?