I don;'t think they do cross but Lucifer is a bit peculiar - I notice some years its distinctly orangey red and other years (like this summer) its red. Also some years it gets to 4.5 feet in my garden, most other years its about 3, 3.5 feet tall - this year was a shorter, redder year!

They do cross - and that is why there are hundreds of crocosmia varieties. Self-seeding is rare though and nearly all multiplication you see in a garden is due vegetative reproduction of the corms.
In my experience Lucifer will be more orange if it is underfed and/or is short of sunlight. Especially the latter.

This year has been a funny year for flowers to be a different colour to usual. I've had a few and other members have also commented on changes to colour this year.

Ah, Buddlejag.... I sat and thought about it after I typed my answer last night and realised that, in the years they are tall and more orange, the weather had been fairly consistently dull with plenty of rain about. I already realised the height could be accounted for by duller, wetter weather, but hadn't made the connection with flower colour. This year they were shorter and redder, and we've had a lot of sun from mid June onwards.

Jothe gardener: The point about possible cross breeding is that, even if they produce seed, it doesn't usually grow anyway, not left on its own, and having Crocosmia masonorum in the same garden as Lucifer does not mean there will be an impact on either plant.