I saw that same thread and already told the person it was incorrect. A new user tried to argue about it so they went straight onto ignore.
What a beginner error. I was mixing a vial of Reta. Drew the liquid from the vial into the syringe, stuck a spare diabetic needle into a cartridge, then inserted the Reta with its filter and new needle. I had just read about someone using a diabetic needle for venting by not pulling the plunger and simply letting it rise as liquid entered the cartridge. I figured that was a decent middle option between leaving a needle open and using up a filter on the vent. Tried it myself. Naturally the rubber stopper in the cartridge came out the bottom instead of the plunger moving, and a third of the vial ended up on the counter.