BT.601 mixed with BT.709 in ProRes

[gs684]

I have recently created a bunch of ProRes master edits using various footage from both SD and HD movie sources.

The mediainfo for the HD ProRes exports shows all Bt.709 information:
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709

On the other hand, the mediainfo for the SD ProRes exports shows mixed Bt.709 & Bt.601 information:
Color primaries : BT.601 NTSC
Transfer characteristics : BT.709
Matrix coefficients : BT.601

Does anyone know why this is? Shouldn't the SD version show solely Bt.601? Is there any problems with this result?

[poisondeathray]

It does not matter for transfer characteristic - because it's the same for bt601 and bt709.

You can refer to Table E.4 in the ITU h265 document for a definitive reference