[Plugin: SEO SearchTerms Tagging 2] Auto clean up stopped working

Hi,
I have a little issue with SEO STT2 plugin. I just noticed yesterday that the “auto clean up” section read:

Last database cleaned up: December 21, 2011, 2:08 PM; 12 search term(s) deleted.
Next scheduled database clean up on December 22, 2012, 7:08 AM.

I tried de-activating the plugin, the reactivating it, and now it reads:

Last database cleaned up: December 21, 2011, 2:08 PM; 12 search term(s) deleted.
Next scheduled database clean up on February 15, 2012, 7:08 AM.

My guess is that somehow the auto clean up stopped working in December 2011 (WP update ? I do not remember). The rest of the plugin actions are OK.

Anybody experiencing the same thing ? I use WP 3.3.1 with SEO STT2 v. 1.53.

Thank you for your feedback!

Cyril

https://www.ads-software.com/extend/plugins/searchterms-tagging-2/