HI - just tried your flow - not seeing any problems so far - which custom properties are causing issues ?
If you uncomment this bit.
// type: msg.payload.value.type,
It fails on my setup.
It is a good few years since I last did much Java. Does putting quotes round the element name have any significance?
Ah right yes - an issue co-incidentally just fixed in 2.8.6
type was being used as a simple discriminator for geojson type input - so I have beefed that up a bit.