Un-caught exception when using a transacted route with @receipientList through direct-vm

We have a transacted route which calls a route which contains the @recipientList annotation (through a direct-vm).

Within the direct-vm route, the route calls a 'down' http endpoint. This results in an exception being thrown (due to the connection refused) - but this is not caught by the onException handler in the calling route. If the calling route is not transacted, the route works.