ejabberd服务器消息无时间戳及记录重复问题求助

我搭建了一台ejabberd服务器，创建了两个用户（admin和user1），并使用基于浏览器的XMPP客户端实现二者间的通信。

问题1：请求MAM数据时消息无时间戳 #

请求MAM数据返回的消息中时间戳字段均为0：

flutter: {customText: , from: user1@myejabberedserver.com/converse.js-86119887, senderJid: user1@myejabberedserver.com/converse.js-86119887, time: 0, id: a4228800-d556-4f42-882b-897cca5b3dea, type: Message, body: hi, msgtype: chat, bubbleType: , mediaURL: , isReadSent: 0}
flutter: {customText: , from: admin@myejabberedserver.com/converse.js-33482782, senderJid: admin@myejabberedserver.com/converse.js-33482782, time: 0, id: 8315a148-7c72-4174-b188-cb976126c7ae, type: Message, body: , msgtype: chat, bubbleType: , mediaURL: , isReadSent: 0}
flutter: {customText: , from: admin@myejabberedserver.com/converse.js-33482782, senderJid: admin@myejabberedserver.com/converse.js-33482782, time: 0, id: 4dcec56e-5e55-4e72-8adc-f064f662af26, type: Message, body: hello user, msgtype: chat, bubbleType: , mediaURL: , isReadSent: 0}

问题2：数据库存在重复记录 #

数据库中出现多条完全重复的消息记录：

<message xml:lang='en' to='admin@myejabberdserver.com' from='user1@myejabberedserver.com/converse.js-86119887' type='chat' id='cf64cb88-5e51-451a-8c3e-b394418ee7e7' xmlns='jabber:client'><received xmlns='urn:xmpp:receipts' id='4dcec56e-5e55-4e72-8adc-f064f662af26'/><store xmlns='urn:xmpp:hints'/></message>
<message xml:lang='en' to='admin@myejabberdserver.com' from='user1@myejabberedserver.com/converse.js-86119887' type='chat' id='cf64cb88-5e51-451a-8c3e-b394418ee7e7' xmlns='jabber:client'><received xmlns='urn:xmpp:receipts' id='4dcec56e-5e55-4e72-8adc-f064f662af26'/><store xmlns='urn:xmpp:hints'/></message>
<message xml:lang='en' to='user1@myejabberdserver.com' from='admin@myejabberdserver.com/converse.js-33482782' type='chat' id='8315a148-7c72-4174-b188-cb976126c7ae' xmlns='jabber:client'><received xmlns='urn:xmpp:receipts' id='a4228800-d556-4f42-882b-897cca5b3dea'/><store xmlns='urn:xmpp:hints'/></message>
<message xml:lang='en' to='user1@myejabberdserver.com' from='admin@myejabberdserver.com/converse.js-33482782' type='chat' id='8315a148-7c72-4174-b188-cb976126c7ae' xmlns='jabber:client'><received xmlns='urn:xmpp:receipts' id='a4228800-d556-4f42-882b-897cca5b3dea'/><store xmlns='urn:xmpp:hints'/></message>

内容的提问来源于stack exchange，提问作者user1354934