notifications on old posts suddenly sent after update today

One of my sites using Email Subscribers spontaneously sent out post notifications on 4 old posts after the update today. Luckily, I am the only person on the mailing list for that site, and it did not do this on any of my other sites that have the plugin (and which do have subscriber lists), so no harm done. But I thought I’d mention it in case anyone else also experienced this. The update was applied automatically by another plugin, so I don’t think I was even logged in to the site today.