Unfortunately, the notification emails started again a few days after the WP4.4.1 update. May therefore be a bug in this plugin after all. Is there any info I can provide to help you investigate?
The emails whenever “[a] comment is held for moderation” (WordPress’ Settings | Discussion). Before the WP4.4, that setting did not result in emails for spam comments. BUT: I just see in https://codex.ww.wp.xz.cn/Version_4.4.1 that a bug regarding that has been fixed in WP itself.
My apologies for this false alarm.
Same problem if any other kind of HTML tag is used. <sub>, <sup> and <a> in my case.
