My immortal phoenix died of a disease??

[Edi]

Graeme Dice said:
It's a bug that's been around for a long time. If any immortal unit is killed by a disease, then that unit is permanently gone, no matter what the local dominion is.

First that I heard of it. Are the mechanics different from Dom2? In Dom2, if a diseased immortal unit died, it came back the next turn and promptly died again and again until the disease affliction disappeared on respawning.

Does it work the same or has disease been made a non-triggering cause of death? If it's changed, it needs to be shortlisted immediately, but I've not seen this mentioned before.