Subscriber must reset DataSetMessage SN after certain amount of time
According to OPC UA specification part 14 v1.05 section 7.2.2.3:
Subscribers shall discard the records they keep for sequence numbers if they do not receive messages for two times the keep alive time to deal with Publishers that are out of service and were not able to continue from the last used SequenceNumber.
[Edit JCH]: In addition, I think the application should get a notification that this event happened.
Edited by Jérémie Chabod