I am running a once-daily sync script against your v2 endpoints to create contacts and add existing contacts into lists. I am observing new behavior where the list association changes for unknown reasons. I have numerous contacts which, after my script completes, are part of at least one, in many cases 3 different lists. The account record looks something like this in json:
When I rerun the script 24 hours later, there are many contacts which are suddenly removed from all lists and have the status "REMOVED". What can cause these automatic list removals with Constant Contact? This happens without any additional API or UI interaction.