Originally Posted by Raze

It works fine here (on PC), with regular and high quality fire essences, and a couple of different empty potion bottles (small, with a cork stopper, and slightly larger with a glass stopper).

Are you using any mods that might change recipes?

Try verifying local files: in the Steam library, right click on the game and select Properties, switch to the Local Files tab and then click on the 'Verify Integrity of Game Cache...' button.
With the GOG version, in the (optional) Galaxy client, select Divinity: Original Sin 2 in the left column, then click on the More button, and in the Manage menu select 'Verify / Repair'.
With the App Store release, or GOG without the Galaxy client:

cd ~/Library/Application\ Support\ ... up to the Divinity Original Sin 2.app folder
codesign -vvv Divinity\ -\ Original\ Sin\ 2.app

For the first command, it may be easier to browse to the install folder in Finder, then drag and drop the location into an open Terminal window.
The second command takes a while, and will output some lines starting with '--prepared' or '--validated'. If everything is fine, it will end with:

Divinity - Original Sin 2.app: valid on disk
Divinity - Original Sin 2.app: satisfies its Designated Requirement

Yeah super weird, everything checks out... I don't use any mods like that either, no. The only mods I really use are the odincore and helaane class mods. I use summoning tweaks, and a few others that really shouldnt interfere with that... grrrr those potions are SOOO good for glass cannon builds man I NEED to figure this out! lol