Subscribed to the aforementioned notifications. A colleague commented on a security hotspot assigned to me, and I received an email ("[SonarCloud] A manual update has changed some of your issues/hotspots") which contained a link to the security hotspot - however, the link fails to open (“The page you were looking for does not exist.”).
Link in mail was along the lines of:
h-t-t-p-s://sonarcloud.io/security_hotspots?id=PROJECTNAME&hotspots=SOMEHOTSPOTID
…whilst a permalink created from a security hotspot includes /project in the URL:
h-t–t-p-s://sonarcloud.io/project/security_hotspots?id=PROJECTNAME&hotspots=SOMEHOTSPOTID