Hello, i have recently noticed a bug that has to do with brewing stands: it is that when bottles are taking out of a brewing stand through the use of a hopper, the brewing stand does not realize the bottles were taken out, thus not allowing new bottles to come in via another hopper. This is basically it, but it completely ruins auto potion breweries. I will include a link to a Mumbo Jumbo video where he too notices this bug.

Mumbo's Video: https://www.youtube.com/watch?v=97sFP1a9ji4
Skip to 6:13 to where he explains the bug.