diff --git a/src/Socket/messages-recv.ts b/src/Socket/messages-recv.ts
index 1f6f909c..53723194 100644
--- a/src/Socket/messages-recv.ts
+++ b/src/Socket/messages-recv.ts
@@ -2232,6 +2232,10 @@ export const makeMessagesRecvSocket = (config: SocketConfig) => {
 						msg.messageTimestamp = +node.attrs.t!
 
 						const fullMsg = proto.WebMessageInfo.fromObject(msg) as WAMessage
+						// Preserve custom WAMessageKey fields (participantAlt, participantUsername,
+						// addressingMode) that proto.WebMessageInfo.fromObject strips because
+						// they aren't part of the proto.MessageKey schema.
+						fullMsg.key = msg.key
 						await upsertMessage(fullMsg, 'append')
 					}
 				})