The session times out after a few hours and one can't schedule new recordings and also the config button disappears from the guide page. Deleting the cookies and reentering NEWA guide via a saved bookmark will workaround the issue. All 3 of my nPVR boxes have the issue. On 2 I'm using whatever version NEWA was installed with nPVR v2.4.3 and on the 3rd box nPVR v2.5.5 with the NEWA v1.26 updates. I've tried Firefox 184.108.40.206, 3.6.28, 10.0.2, Opera 11.52, Internet Explorer 8.0.6001.18702 and concluded it's probably not the browser.
I googled it and found info suggesting starting the ASP.NET service and then changing the ASP.NET mode from InProc to StateServer. I tried that and it seemed to help a bit (maybe I imagined it..I don't remember...), but it didn't fully fix the issue so I changed it back. There was also some discussion about needing code to "serialize" the session, which I tried to follow, but somewhat over my head..
I usually only connect to NEWA once a day and I found that as long as I first delete the cookies and then use my bookmark to get to the guide, the issue stays away. Kind of a kluge workaround, but whatever.. not a big deal but thought I'd post and see if anyone else has seen the issue.