Does anyone else get this or is it just me?

I'm logged into eBay (freshly, a few minutes ago, so it's not an expired
24hr session issue). Happily using My Ebay etc. Go into one of my listings
and click "sell a similar item" and it asks me to log in again. I put my
credentials in and bash Enter. They're accepted, but it redirects back to
the login page again. Repeat ad infinitum.

The only way I've found to fix this is to delete all eBay cookies and start
from scratch. Restarting the browser (Firefox) isn't enough.

Just very annoying....