I have a similar problem with this. I'm using GFE 18.104.22.168 and the latest recalbox.
I successfully paired recalbox and moonlight. Could not scrape as it said thegamesdb was down but the games do show up in my list under moonlight in emulation station.
When I attempt to launch any games I get stuck to the black loading screen (with recalbox logo on bottom) and it just stays there.
Unlike the OP if I run 'moonlight stream' I get an error that says I need to pair first. But if I run '/.Moonlight.sh pair' again I get another error saying that I'm already paired.
So I can do nothing but reboot. No games will launch at all.