I strongly suspect this has something to do with the one-step ahead prediction and is probably also responsible for the routing issues when preparing food. I believe (but can't positively confirm) that even with autonomy turned off, the game will invisibly queue another action for sims which have been issued commands, and, in order to "intelligently" move to satisfy the issued command and the ghosted command in the shortest possible time, the sim will move towards the ghosted command's target before proceeding with another step in the current command's linked set of actions. A few examples of this are:
1. (this can be verified, and shows there's something a bit wonky with the 1-step ahead prediction) queueing call geological council, then dig first runs the sim up to the dig site, initiates the call, then performs the dig (as opposed to call, run to site, then dig, as would be expected)
2. (this is what I suspect is happening) when doing a food prep, the sim moves towards a distant counter to do part of the food prep; I suspect that there's a ghosted "dance to stereo" to a stereo near the distant counter that's causing the sim to do the chopping at this very distant countertop; unfortunately the prediction isn't smart enough to know that you're going to need to take that food all the way back to the kitchen to keep cooking (and also irritatingly ignores the 'Disable Autonomy' setting in the options)
It's obvious that there *is* one (and exactly one) step ahead prediction, as if you issue a 'greet' command this will halt the sim targeted for greeting if the greet command is the next one in your action queue, but not if you place it further down on the action queue. This kind of prediction could also reasonably account for the whole musical chairs thing as well.