I had the same ghosting issue. Upgrading the base software alone does not get rid of it. You have to upgrade the transponder too.
Scott- 2018 dues paid
Got medical back, now building a 7A.
RV-12 #120515, 319RV 1st flight 12/2015 now over 260 hours.
RV-9A, 536 hours sold, RV-7 sold, Kitfox sold