v.6.0.1: Cron Job Warning with empty argument

[AlexKa]

Expected behaviour

Crons should run without warnings

Actual behaviour

Warning appears in admin..

Steps to reproduce

Not sure..

Server configuration

Operating system: SMP Debian 3.2.51-1 x86_64

Web server: Apache

Database: Mysql

PHP version: 5.3

ownCloud version: v.6.0.1 (updated from 6.0.0)

Apps installed:

Activity
Deleted files
Documents
Encryption
First Run Wizard
Full Text Search
ownCloud dependencies info
PDF Viewer
Pictures
Share Files
Text Editor
Updater
Versions
Video Viewer

The Warning:

Warning PHP call_user_func() expects parameter 1 to be a valid callback, first array member is not a valid class name or object at owncloud/lib/private/backgroundjob/legacy/queuedjob.php#32   2014-01-30T08:45:02+00:00

Mysql:

Here's an empty argument?!

Some Debug infos that might help:

        var_dump(
                $argument,
                array($class, $method), $parameters
        );

        debug_print_backtrace();


Output:

NULL
array(2) {
  [0]=>
  NULL
  [1]=>
  NULL
}
NULL
#0  OC\BackgroundJob\Legacy\QueuedJob->run() called at [owncloud/lib/private/backgroundjob/job.php:34]
#1  OC\BackgroundJob\Job->execute(OC\BackgroundJob\JobList Object (), OC\Log Object ([] => OC_Log_Owncloud)) called at [owncloud/lib/private/backgroundjob/queuedjob.php:27]
#2  OC\BackgroundJob\QueuedJob->execute(OC\BackgroundJob\JobList Object (), OC\Log Object ([] => OC_Log_Owncloud)) called at [owncloud/cron.php:103]

[VicDeo]

Duplicate of #8500