PHP process hung and ran for 575160 seconds

I recently had a problem with my hosting,
wp-content/uploads/wysija/themes/mailp/index.php
hung and ran for 575160 seconds!

That happened a couple of days ago, i have not been using WordPress at all.
No new posts were written for last couple of months, so nothing was scheduled for
e-mailing.

Any ideas what might be wrong?
Possible bugs?

p.s. it was likely version 2.6.8, or possibly one before, as I updated some plugins (don’t remember which) before I realised it is related to Wysija

https://www.ads-software.com/plugins/wysija-newsletters/