DDJ-800 External Inputs and PC Master Out

UPDATE 13/5/20 6 months later and no fix, stopped hearing from Pioneer support in February

Just bought DDJ-800. So far:

- External phono/line inputs do NOT work when rekordbox is connected to DDJ, but do when it is not. 

- If I have a channel on phono when rekordbox is connected, phono input will come through for a second if i toggle the PC Master out setting (in either direction) but it always turns off again straight away.

- Microphone inputs only work in low latency mode. If I switch to effect mode I get no microphone output.

Hardware is MacBook Pro (Retina, 13-inch, Mid 2014), 3 GHz Dual-Core Intel Core i7. MacOS Catalina 10.15. I had already installed Catalina when I bought the DDJ.

Rekordbox version is 5.8.1