I don't think coming into conclusion for other users are a wise move.
Anyways, I logged many times everyday (you can check the system log again), I checked my rosters more than 10 times a day for their skills so that i can make my lineup for the games.
Once again, I'm 100% sure + 100% guarantee that the arrows on stamina was not there for the whole week.
Also, I used IE at office, Firefox and Chrome at home, and the 3 browsers didn't show it too. So, any other conclusions you want to imagine or simulate ? I can respond it and also you can check on your own game log to prove it too.
Unfortunately, I didn't have any screenshots with me....