UKH

Just bought a Beal Opera.

The mid-way mark has caused that area of the rope to narrow slightly and stiffen compared to the unmarked rope. If this were an accidental stain on the rope I would retire it - but given that it's deliberately marked by the manufacturer I'm assuming it's OK?

Anyone experienced this?

I'v used beal's rope marker ink rolly thingy in the past. It caused the rope to become noticeably stiffer over the inked section. It softened up reasonably with a bit off use. 

Assuming they use the same ink in the factory, I'd expect it to soften with use. Give it a good working over by hand, see if it starts to give. 

My Petzl Contact was the same, it's fine.

It will soften (and fade) over time.