It shows an 18+ tag for me too, and the image is blurred. I assume it's because of our host software. I'm on kbin.melroy.org (Mbin), and the original commenter is on moist.catsweat.com (also Mbin).

curiously someone asked me about it but before I could answer as it was my overnight a whole chain went up with folks that solved the mystery. Its something that for some reason is not showing between lemmy and mbin. So mbin users should (not) see it while presumably lemmy users will not realize the tag is there. Honestly I would like mbin to allow me to ignore the tag but apparently saying show nsfw just means the feed will show but it does the tag thing. Don't get me wrong I would use it but only if users kept to to blocking just completely graphic stuff. I would rather see the graphic stuff than the rediculously mild stuff that gets blured. Maybe its mbin users with the dainty feelings.