Overview: using js client in command mode with snapshot=true.

Our clients don't have insight into all the items that could be published to them, so we are using a global item to subscribe to ("FLIGHTS") with a unique "key" assigned to each flight so that the client can properly associate data rows (answer the question "do I have this row already?"). The data adapter has a REST endpoint to gather all the flights which meet the publication criteria and return them. Data updates are pushed using "ADD" because the producer doesn't really know if a particular key has met the conditions for publication any time prior, it just knows it needs to be published now.

The phenomenon we are observing is that although initial state is reflected properly at startup and new (and subsequent) events process through the system as expected, if a client refreshes their browser, not all data is republished to that client.

So, a couple of questions come to mind:
1 - is there a more appropriate mode (merge?) that we should be using?
2 - are there any tools we can use to see what is in the LS kernel cache to identify where our processing logic is flawed?

Thanks for your time.