The problem is with a device running Windows 7 that is configured with some shares to its local drives like a storage server.
Every so often no one can connect to the shares, Android users just see a spinning/processing icon and windows users get a variety of connection error messages. The end result is always the same, no connection.
The only solution is to reboot the Windows 7 device and things have gotten so bad that now they have a scheduled script that reboots the computer daily.
I asked them to capture some packets from their computer when it happens again.
By noon I had a capture.