In Firefox (v 87) I am getting signed out of my Esri login when I open one of the developer pages. For example, I am logged onto the Community and open theArcGIS Pro SDK page. The page opens for a second, then I get the message that I am signed out. If I go back to the Community site, I am logged out of that also.

I have tried this in Chrome (v89.0.4389.114) and when I open the SDK page, it logs me in with my Community credentials.