Hi Brian Peat,

I am sorry for the delay of this reply.

Regarding your issue, look like there is a bug on token checking in EasyBlog's unsubscribe function. I've fixed the issue internally and the fix will be added into next release of EasyBlog. By the way, i try to apply the fix on your site but the ftp account that you provide us failed to authenticate me

Can you download the attached subscription.php and copy the file to folder JOOMLA/components/com_easyblog/controllers/ and overwrite the existing 'subscription.php' file. Remember to backup your original file first before you overwrite with the updated version

Let me know if the attached file fix your issue or not.
Hope this help and have a nice day!