When I login on a question, it looks like I have upvoted all comments

I get the following unexpected behaviour when I access mobile web versions of Stack Exchange sites through Google Chrome on Android. If I am logged out, visit a question, then log in while on the question page, all of the comment upvote arrows on the question turn blue, appearing to me as if I have upvoted every comment. Once this has happened, the blue arrows persist even if I leave the page and return, and even if I log out and log back in on a different page. I cannot reproduce this bug on other computers.