TYPO3 Core

When trying to enable permissions on the live workspace for a user, this change is not saved.
Even updating a user which has this permission, removes the permission.

The log shows "Record 'foobar' (be_users:123) was updated. (Online). Changes in fields: usergroup,workspace_perms. (msg#1.2.10)"
but this is not reflected in the databases and the box will be unticked in the form after saving.

There is no error message to the user.

I don't know if this is related but I sometimes see the error messages

Core: Error handler (BE): PHP Warning: Invalid argument supplied for foreach() in /var/www/typo3/typo3_src-4.6.2/typo3/sysext/workspaces/Classes/Service/Workspaces.php line 409
Core: Error handler (BE): PHP Warning: array_diff(): Argument #2 is not an array in /var/www/typo3/typo3_src-4.6.2/typo3/sysext/workspaces/Classes/Service/Workspaces.php line 402
Core: Error handler (BE): PHP Warning: array_keys() expects parameter 1 to be array, null given in /var/www/typo3/typo3_src-4.6.2/typo3/sysext/workspaces/Classes/Service/Workspaces.php line 402

in the logs.

I have two draft workspaces only one of which I currently use. My database compare shows no errors
and a mysqlrepair on all tables did not fix this.