Teiid Designer sends header-accept="application/xml" when trying to import from REST JSON

I have my small web application that should simulate a REST web service (it simply returns XML and JSON strings), when I have annotation @Produces("application/json") and I try to import from this REST JSON, TD gives me an error that server returned response code 406.

After I change it in my application to @Produces("application/xml") it is OK.

I tried to force server to log accept-headers that it is sending. Server sends accept-headers: aplication/xml (Log attached)
Screenshots attached

TD 8.6.1.Alpha1 + DV 6.1.ER2

I am not sure, but I think this issue occurs also in 8.3.4