Ghost Images on PowerFLARM?

Using a Portable PowerFLARM the first time a few weeks ago I noticed that there were sometimes two targets for a given glider. When I first got near the glider and it showed up on the screen, it was a "hard" target on the built-in display. Once I was in the thermal, however, sometimes that hard target would be supplemented by a ghostly image near it. I was wondering if that was the previous target that the FLARM was trying and failing to verify without processing that the "new" target was the same one that had been displayed some seconds before.

Anyone had this happen? It wasn't a big deal at the time but I'm a little concerned it would/will be with 50 gliders around at Elmira.

Chip Bearden
ASW 24 "JB"
U.S.A.