I would like to file a report on odd behaviour regarding hoppers and brewing stands.

As far as I am aware, brewing stands take bottle inputs from a back hopper; output it a hopper below.

Have a hopper input into the brewing stand, above a chest filled with water bottles, lock it. Hopper output out of the brewing stand, into a chest, lock it, nothing flows through, as suspected, now you unlock the hopper bottle input, bottles will flow into the brewing stand as they are supposed to. Lock the bottle input, then unlock the output. The bottles will get taken out of the brewing stand into the chest, as usual, and no bottles will get in, since you locked the input. Now lock the output, and unlock the input, this is where it isn't functioning normally anymore. No water bottles will flow into the brewing stand. no matter what, it's not being powered or anything. However, replacing the brewing stand or reloading the world entirely will make the bottles flow in.

Just wanted to address this, I know its hard to understand, the way I put it, but look at the attachment and try to recreate it, you will find out for yourself that it isn't working as it should.