TYPO3 Core

If i left backend unused for a while i will get popup window with login form when session expires. If i try to login now first attempt always fails and i have this entries in log:

22:12:32     admin@[-99]     LOGIN     LOGIN     User admin logged in from 127.0.0.1 () (msg#255.1.1)  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'uid' in /typo3/sysext/backend/Classes/Controller/LoginController.php line 222  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'uid' in /typo3/sysext/backend/Classes/Controller/LoginController.php line 431  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'uid' in /typo3/sysext/backend/Classes/Controller/LoginController.php line 381  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'uid' in /typo3/sysext/backend/Classes/Controller/LoginController.php line 183  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'options' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 1557  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'admin' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 366  
22:12:22     [0]@[-99]     [5]     [0]     Core: Error handler (BE): PHP Warning: Illegal string offset 'uid' in /typo3/sysext/core/Classes/Authentication/BackendUserAuthentication.php line 2212  
22:12:22     [0]@[-99]     LOGIN     ATTEMPT     Login-attempt from 127.0.0.1 (), username 'admin', password not accepted! (msg#255.3.1)  
22:12:22     [0]@[-99]     LOGIN     ATTEMPT     Login-attempt from 127.0.0.1 (), username 'admin', password not accepted! (msg#255.3.1)

Second try will result with valid login.