I don't think that is a bug at all. if you are powering up with Steem then they use the Steem logo for that. It makes little sense to use the Steemit logo for this process. In fact, they created the new logo for the purpose of seperating Steemit and Steem in the public opinion.
I wouldn't change it, if it would be up to me.
Oh! That makes sense! thank you =) If this doesn't get approved I will know why
But come to think of it, it could be a bug, considering they left that icon somewhere else too... https://steemit.com/steemit/@overkillcoin/bug-hunting-old-steemit-favicon-shows-up-in-android-firefox-history
So it might be worth to take a look.
Right, thats something different and is indeed probably a leftover change to do.