I tried to apply CU updates last night and they failed so we rolled back our snapshot. Everything seemed to be working last, I didn't go through every single site in our Farm, just did a spot check. This morning someone received an error accessing their site:
"The context has expired and can no longer be used (Exception from HRESULT: 0x80090317).
The logs is showing a "Logging Correlation Data" for that correlation error.