Assuming you are playing on mobile, this is a known issue.
Good news, it is supposed to be resolved since build #37 (update 1.5.6.37) that was released yesterday or two days ago, depending on where you live. Thus, I suggest that you update your game to the latest version.
A workaround was also found: by placing all your gold star vegetables in the top row of your inventory before dropping them into the box at Pierre's. This also works with all Special Orders quests that require you to drop items in specific locations.
For your information, all bugs related to 1.5 update for mobile should be reported in
this dedicated thread.