Thanks for everyone's input.
The FAA has identified that the software which increases the requirements to become a TIS-B client was rolled out in a few service volumes earlier than expected. This change was originally scheduled to start on Jan 4th, 2016, but was then supposedly delayed to February. The partial nature of the roll out also means there is an additional issue that will cause ghosting almost continuously in many situations in these areas.
The known volumes are LAX and Washington DC. This does not mean other areas haven't gotten it, it's just that those are the ones communicated to us. We are aware that SFO has also reported this. It is very likely this is the same issue.
Dynon's next software release will fix this, and is expected very soon.
Thanks for everyone's help, and we're sorry for the inconvenience. On the plus side, the FAA is more than aware that Dynon customers are active users of ADS-B, and they continue to be very responsive to our input and relatively quick to work on solutions when needed.