We made some changes in 4.0.1 Koli to ensure that notifications are sent in case an attempted login to your account fails (it actually attempts multiple times before generating notifications). This is to avoid a situation where you change your credentials on the web, say, but forget to update them on your phone. It’s also an important reminder after restoring a backup, since account credentials aren’t stored as part of the backup.
This might explain why you’ve only started receiving them recently, I’m not sure. It likely suggests there’s some periodic problem logging in to soverin.net, but it’s hard to say what this might be. It may be worth double-checking your settings. You could also collect some logs and review them straight after getting the notification. I’d be happy to check them for you too, but please don’t post logs publicly as they may contain private information.