Marks on caulifower

Hi

I'm looking forward to harvesting our first caulis soon, checking each day to see what growth they're managed since i looked just yesterday... you know how it is.

Today i noticed a few discoloured patches on one of them - with a mauve tinge. The head seems fine otherwise. Growing under enviromesh but nothing's is 100% is it?

i was considering bending the leaves over to protect the heads from sun. Is this why it's done?

Any suggestions?