Agree, include it your resume as just another fact regarding your current job.
One way it could hurt you.
When you're on your intirview and the interviewer is going over your resume and comments about and asks about your clearance and you start bragging about all the "cool" stuff you "got to know". Shows you can't keep your mouth shut regardless of your clearance.
Don't laugh it happens. About 20 years ago in the private sector my company was involved in the AFOS Weather System. I was recruiting for a project team. A candidate did just that to me. He started a long winded discussion of all kinds of stuff. Well, needless to say I didn't hire him and because of the content of his conversation and also the fact that I might been being tested, I reported the incident to our assigned DIS agent.
Never heard anything back. So either I passed or what happened next was none of my business!