This is an interesting bird. Looking at photos of Fujian and Rufus-bellied Niltava one thing that strikes me is that the crown of the Rufus-bellied Niltava is solidly bright iridescent blue. On your bird, the crown appears more like a Fujian Niltava.
Rufus-bellied Niltava is currently in Category F. I don't know whether that means the record of that species was considered unsatisfactory by the RC or the bird was considered to be of captive origin.