problem

On analysing the linked TS-2825 issue it happened multiple times that sessions were getting lost.

After looking around, one time the session was looking like this in the DB:

| XXXSESSION_IDXXX | zfExtended | e58AUTHTOKEN57c |       NULL |    36000 | NULL    |     33 |

So the modified timestamp and data field were null. This would explain the loose of sessions when using multiple POST /session/ requests for a specific user.