It is commonplace that if one has Patentcenter open in two or more browser windows in the same browser, the “signed in” status will be inconsistent between the various browser windows.
Because the problem is intermittent, one assumes that this is not merely some coding error that can be fixed consistently by means of a simple correction of one line of code. Instead there are probably weird “race conditions” between internal processes within various USPTO systems, or synchronization failures between various USPTO systems. The problem is probably a very deep and difficult-to-fix problem rather than a simple fix-a-line-of-code problem.
I expect this is a “failure to scale” problem. As more users log ino and use Patentcenter, the various systems that are supposed to work together to provide a seamless user experience end up failing to keep properly in touch with each other.
This is trouble ticket number CP36.