After a Minecolonies citizen died, a shadow appeared and it's ghost was invisible instead of showing the citizen. The same happened in the GUI. Once morphed, the citizen is visible.

Are there any errors in the log?

No, no errors showed in the log.

Won't fix, because those entities spam in the log with message:

[17:03:40] [Server thread/WARN]: EntityCitizen '7a527cdb-3b72-4a04-8c10-0a51553d2430' attempting to register with Colony #1 as Citizen #1, but already have a citizen ('23753d4a-7c2b-49eb-a056-f61afb6b39e2')

It doesn't seem to save the model of the citizen, and the problem of its invisibility, is that it's setting up the texture during loop as opposed during the reading entity data from NBT.

Ok, thanks anyways, at least it works after morphing.