Just a small bug. I'd consider this /very/ low priority.
I happened to be frantically spam clicking my herbs, as you do, with a full inventory to grab the ones I had space left for in the stacks, and my character model suddenly 'picked up' one of the herbs (I THINK this is mint, I may be wrong) with their knees and carries it around like that as it flickers in and out of existence.
Restarted the game and it was gone, simple!
Hey thanks for reporting that bug. We will see what we can do about it.