I noticed that when someone answers my message, there is high chance that after a while this same response will come again for no apparent reason. Delay of duplicate varies from 20 min to 2-3 days. Duplicates are time-stamped with the time of arrival. I only noticed this with replies, not the originals.
However, when I shut the client down and restart it, only the latest duplicate would stay, and the earlier version would disappear. So the time on the message would be entirely wrong.
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