If the VA notified me 7 months ago that they will reduce my monthly benefits, and they still haven't reduced my pay, should I notify them?

I would DEFINITELY CONTACT THEM! If NOT, be prepared to get ZERO while they RECOUP Your OVER PAYMENT! The VA dont forgive indebtedness based on "I didnt know!" But they do work with you to take back the over payment so it produces less negative impact on the Veteran.

I hope you are saving the overpayment for when they finally figure it out and want it refunded to them. Even tho it is their 'fault' you may have been overpaid, you still end up getting shafted.

Let sleeping dogs lie. As long as you are being paid enjoy. Same with repayment. You may be dead and gone before they remember you