Some Reddit users have noticed that they can’t sign-in to their accounts anymore on mobile, as the option to do so has been removed for them. Reddit has made it difficult in the past for users to access the site on mobile in browsers. The company’s main intention is to get users to use the official Reddit application instead.
I have it installed as well but as a dark theme user the flashing transitions was starting to get a little annoying.
I installed an update yesterday and that bug is fixed now.