I use the 300XL and have flown that approach but haven't seen that
before (yet). Will be looking but don't have any thoughts other than
what's been said.

Have you tried the same approach since?

Steve S wrote:
I was flying a practice approach today and loaded the approach (Full
approach GPS 20 at RUQ, Rowan County, NC) into my Garmin 300XL. I flew the
approach from initial fix to the final fix but the approach never armed and
consequently never activated. The approach showed as active on the route
page but the annunciator light (arm or active) never lit. The message page
said the approach was not active.
Has anyone experienced this before?