Thought I knew about hyphens but this has puzzled me...

[knpeppa]

This is the correct use of the hyphen as I understood it:

1. XXX is a high-profile event
2. XXX has a high profile
3. High-profile though XXX is ...

A colleague said they would not use the hyphen in the third example.

Who is right? Are we both right and should agree to differ?

I'd use the hypen in the third example. In 1 and 3, high-profile is used as an adjective.

Colleague is right. Hyphen used for adjectival form.

Can you explain that, chipbutty?