[Communication - Chat]ChatThreadClient successfully sends read receipt failing in nightly runs

[zzhxiaofeng]

Communication - Chat nightly test runs are failing with:

Error message:
{ "CommunicationError": { "Code": "NotFound", "Details": [] } }

Stack trace:
RestError: {
"CommunicationError": {
"Code": "NotFound",
"Details": []
}
}
at handleErrorResponse (D:\a_work\1\s\sdk\core\core-client\src\deserializationPolicy.ts:255:17)
at deserializeResponseBody (D:\a_work\1\s\sdk\core\core-client\src\deserializationPolicy.ts:159:43)
at processTicksAndRejections (node:internal/process/task_queues:95:5)

For more details check here:
https://dev.azure.com/azure-sdk/internal/_build/results?buildId=3104913&view=results

[rjgotten]

Currently maybe being bitten by this.

It appears that I'm not receiving a proper "readReceiptReceived" event from the StatefulChatClient in @azure/communication-react at all -- and that implementation just proxies to the base ChatClient from @azure/communication-chat.

If I perform a listReadReceipts the read receipts are there - i.e. they were actually sent.
But the corresponding event is never properly raised.

This is making it impossible to implement a reliable way of reporting unread message count in UI, without manually tracking when a user has opened a particular chat thread in said UI -- and then just brute-force forcing an update that wipes a counter being kept for that thread ID, resetting it to 0. Simply assuming that because a particular chat thread received focus in the UI, all its messages were read.