I am getting the following errors in my PHP error_log:
[16-Jan-2013 22:05:58 UTC] PHP Warning: mb_stripos(): Empty delimiter in .../wp-includes/functions.php on line 658 [16-Jan-2013 22:05:58 UTC] PHP Warning: mb_stripos(): Empty delimiter in .../wp-includes/functions.php on line 661
I compared the error log with the access logs, and found that these errors happen when the server
POST's to wp-cron.php.
What might be causing this? I did not get this error before upgrading to WP 3.5. I realize that this is only a warning, and I know how to silence it. I would just like to know what might actually be causing it. I think it might actually be causing wp-cron to fail, though no other errors are logged, because my site has not been automatically running the backWPup backups like it did before.
Any advice would be greatly appreciated. :)
P.S. I am using PHP 5.4, if that makes any difference.
If you search Google with that error you will see that there are other people having the same problem.