Are direct messages broken?

I just followed an old contact with a new account on libranet.de. When I try to send him a direct message, his new handle does not pop up. No matter how I write his address, the message always goes to the same *diaspora account of somebody total different I follow. This *diaspora account also gets all other failed DMs to other folks. Of course, I delete this misguided messages instantly. On the other hand, some contacts work quiet good, even to Mastodon users.