That is so weird, and BTW, if you restart the game, this bug will refresh, and the Inert cap can't be crafted to a wand until you put the caps which can craft a wand normally into the workbench.

The Inert cap seems can record the last normal cap's recipe.

This is the log file:

latest.log

Are you using 1.2 or higher ? It should be fixed there.

yes,1.2.2

This should be fixed now in version 1.2.4, somehow the last completed recipe got buffered, but that should not be happening anymore.