When does Elektron API start responding with "unknown security ID requested" for expired products? is it beginning of maturity date, day or day after maturity date? i.e. 9128203X3=RRPS - when did it start returning unknown security requested?
On the message that you see:
I just tried this instrument with Elektron EMA Java and with Elektron Websocket, and I got back the expected " The record could not be found".
I suspect that what you see is application generated custom log message.
On when exactly the expired instrument is being removed:
For questions that are on how the data content is generated or updated, such as this, the most efficient approach is to ask them directly at Refinitiv Content Helpdesk online, or by calling your local Refinitiv helpdesk number. For this question, I have submitted to content helpdesk on your behalf, the support case # is 08231150 , please expect the response via email.