[snypher]

"When you report a secret conversation, recent messages from that conversation will be decrypted and sent securely from your device to our Help Team for review."

So they either have the keys or a way to force the client to decrypt.

[colejohnson66]

Or it’s decrypted on your side, and you reporting it sends the decrypted form. How else would a “report” button work if not with unencrypted data? Not everything is a conspiracy.