It's not that, I have seen that bug and it has something to do with/or interacts with the fertility stat. I only know this because just for giggles I ramped up the fertility stat on everyone once to about 15,000% and everyone was a blur. I can only guess that something with the goat girl's fertility stat is the cause because she tends to cause a domino effect, without ramping up fertility it only takes a couple days of her with the permit active for her to begin to move faster, shortly there after a few of the others will, not all of them (unless of course you ramp up fertility) but I would have to double check but the goat girl the shark girl, and the fox girl seem to speed up their animations with or without the item regardless of its state. I tried not buying the items that adjust speed and it happened, I noticed it on my end owning both with fast off and slow on, and even not buying the faster item and only owning and activating the slowdown item worked. It's also gradual thing that escalates, so it's not the items...
Quite frankly I have no idea how or why the fertility stat in any way effects animation speed, but let me be clear, I have tested it, and it does. (Shrugs)
(without fertility ramping.) Bunny girl not affected, wolf girl either not affected or takes a long time, kobold girl seems to only be partially affected...
Affected npcs, Goat girl (possible cause) fox girl after a while.