Hi there @Meatballsx it is indeed a bug...and an annoying one at that! My Sims are doing it too, which is clever since they can't possibly have the rare ingredients to make it. Here's the bug thread if you want to click on Me Too on the first post and add a reply if you'd like to do so.
https://answers.ea.com/t5/Bug-Reports/OPEN-OR-De-Stressing-Decoction-everywhere/m-p/11450315#M212500
Some players have found it helps to turn off the Self Sufficiency NAP but I don't have that anywhere so it's not a factor for me.
I need about a gallon of the stuff myself after tidying it all up from around my park BBQs! I wouldn't mind if we could actually gather it up to keep or sell 😤.
Good luck!
