Just received the following e-mail, quickly looked at the title and saw "new items in your Stack Exchange inbox" - at a closer look, it turns out there was just one new item in my inbox, so it shouldn't say "1 new items". Same thing goes for the content, where it says "The following items were added [...]".
Here's a screenshot with the problems highlighted:
It should be a fairly easy thing to fix and it just seems like something that should've been done a long time ago, especially considering the site's technical aspects.