"Potential cache slam averted" error warnings

I’m getting this warning in the server’s error log:
[Tue Feb 25 15:55:14 2014] [apc-warning] Potential cache slam averted for key ‘w3tc_0_dbcache_all_1011817997_key_version’ in /home/humortimes/public_html/wp-content/plugins/w3-total-cache/lib/W3/Cache/Apc.php on line 187.

This one also repeats a lot:
[Tue Feb 25 15:55:14 2014] [apc-warning] Potential cache slam averted for key ‘w3tc_key_www.humortimes.com_0_dbcache_5a2aad7162fa265b09993878b6663a8b_0’ in /home/humortimes/public_html/wp-content/plugins/w3-total-cache/lib/W3/Cache/Apc.php on line 55.

It repeats constantly. Every 3 min, it shows 20 of these exact warning, even the time stamp is exactly the same.

What’s going on?

Any help would be appreciated. Thanks.

https://ww.wp.xz.cn/plugins/w3-total-cache/