I attached two images, I'd thought my export settings were wrong, but after testing I figures out that the loudness normalisation box was causing the problems. The overexposed one is the one with loudness normalisation on - I tried different codecs, QT (422 and 422 proxy) and H.264 (various combinations).
Hi, thanks a great video. I know this though and the sequences were all set up correctly; what I'm saying is, using AUDIO NORMALISATION in the efffects tab in export menu causes a random shift from HLG to Rec.709. No other changes in the export, just ticking that box causes a colour shift.