Dragon disappears into gateway

I already have two gateways, and hoped the latest update would actually get me the third and fourth as well when defeating respawned dragons.
But I have a new issue which is turning it pointless to try.
The dragon flies into a gateway and disappears. The health bar is gone too.
It's a good thing I disabled autosave, because otherwise I'd be stuck in the End with no active portal to get me back.