Chat Export failed

Logs:

Received {"requestId":"3e33d264-1890-41d3-8d6b-4a730550d861","command":"aws/chat/getSerializedChat","params":{"success":false,"error":{"type":"InternalError","message":"Failed to get serialized chat content"}}} from chat
2025-10-02 17:01:10.999 [info] [Error - 5:01:10 PM] [2025-10-02T15:01:10.994Z] lserver: Unable to export tab "5594yg": The "data" argument must be of type string or an instance of Buffer, TypedArray, or DataView. Received undefined
2025-10-02 17:01:11.001 [info] [Info - 5:01:11 PM] [VSCode Telemetry] Emitting amazonq_performChatHistoryAction telemetry: {"action":"export","languageServerVersion":"1.35.0","filenameExt":"","result":"Failed"}
2025-10-02 17:01:11.002 [warning] telemetry: invalid Metric: "amazonq_performChatHistoryAction" emitted with result=Failed but without the `reason` property. Consider using `.run()` instead of `.emit()`, which will set these properties automatically. See https://github.com/aws/aws-toolkit-vscode/blob/master/docs/telemetry.md#guidelines
2025-10-02 17:01:17.831 [info] [Info - 5:01:17 PM] [VSCode Client] Received {"command":"aws/chat/tabBarAction","params":{"tabId":"2e2s2c","action":"show_logs"}} from chat

Start with the VS Code chat export action and the aws/chat/getSerializedChat request shown in the logs, then reproduce the failure and trace why serialized content is undefined. Verify that exporting a chat succeeds and that the amazonq_performChatHistoryAction telemetry includes a failure reason; no source file or test is identified in the issue.

Written by the indexing model from the issue text.