Hey,
I've just looked into this to see if I can find any cause of the issue - and as Sponge said before there have been no recent changes that we can see which would cause this effect. There does seem to be a misunderstanding in how the potion works so just to confirm the potion will aggro 1 mob every 3 seconds; it will not (and never has) aggro'd a whole area at once from what we can tell.
In both your videos above - you can see a new NPC being caught by the potion at each 3 second interval. The first is a bit more awkward to see as some NPCs are getting caught on the scenery, but the second video shows it clearly working as expected.
If you have any more info or could show it not working as mentioned above, please let us know so we can investigate more!