According to https://oss.chat/dashboard/:

The message sent is a few but I know it has already sent a lot of UrlLink and Text messages already.

The reason is unknown but we should always Emit Self Messages: when the bot says anything, the bot should receive a message said by itself. (and the message.self() will return true for this message) by following the puppet specs at https://wechaty.js.org/docs/specs/puppet/#basic-rules