Resolution:
In Lotus Notes Adapter (version 5.3.0) Request-Response Service (RPCS), when encountering a connection issue in the middle of the operation, a reconnect will be performed immediately.
- If the connection regained within this retry, the service will continue its operation on the current request.
- If the retry failed, an error reply will be sent back, though the service will continue its reconnecting. That means the current request is completed with an error reply. In this case, an exception will be thrown by the  ‘Invoke an Adapter Request-Response Service’ activity who calls the RPCS on BW side, so customer could configure the BW process to handle this exception.

This could be observed by performing the test below:
1. Start the adapter with, for example, either Query and/or Insert successfully;

2. Trigger a BW process to send the operation request to the adapter;

3. When the adapter service received the request, and encountered a connection issue during the processing, it will not send back an error reply right away; instead it will immediately do a retry. If the connection regained by this retry, it will perform the operation; if the connection could not be regained by this retry, it will then send back an error reply, so this operation is failed.

4. If you have a timeout value configured in the ‘requestTimeout’ field in the ‘Invoke an Adapter Request-Response Service’ activity in BW process, and the successful reply did not returned before this timeout period, you may encountered a timeout exception instead.

The behavior of Lotus Notes Adapter Request-Response Service (RPCS) when encountering a connection issue