If Lightstreamer Data Adapter interface is implemented correctly,
any snapshot event sent in the middle of the update flow for an item in MERGE mode
cannot add any new information and might even not reach the client.
So, there would be no advantage in extending the Data Adapter interface to add this case.

On the other hand,
if a snapshot event sent in the middle of the update flow for an item in MERGE mode
happened to add new information,
then some update would have been missed in the middle
and the new event would behave as a normal update.

This is why, in a case like yours,
we ask the Data Adapter to adapt the feed interface to Lightstreamer interface,
which means to govern the isSnapshot flag
in such a way that it is sent as false for all but the first event.

However, as a recovery action for an incorrect application of the interface specifications,
we decided not to discard the abovementioned events,
but rather to ignore the isSnapshot flag (with no other effects) and issue a warning.
Notwithstanding that, the warning should be considered as targeted to the implementer/tester,
so as to fix the Data Adapter to become Lightstreamer-interface compliant.