Stop is definitely not instant (it even explains that). Hopefully it finishes (eventually)?
Does it actually upload any new files? Yours seems especially slow. We can look into that if you wish.
Asking on the forum is just going to get lost in noise. This is not an issue tracker. You can file an issue:
but there is quite a long queue of requests.
I poked at this some, and can’t reproduce a half hour delay. Mine ranged from really fast to minutes. Concern early on was that perhaps stop was not coded into the early phase when it’s counting files. Because I have some very large file trees (with small files), I tried one. No problem. You can give an additional hint on what you see on the status bar, the home screen job area, etc. (or ultimately a log showing the activity), and maybe someone can figure out why your stop operation is taking that long.