Is that isolated only to that particular iPhone 5s, or do every SMS thread sent from other phone models behave in the same way?
It could be caused by a wrong time setting, either with your L535, the iPhone 5s or the GSM network (though the last one's unlikely). Make sure that the time is set correctly for all devices. Also check the time stamp of the messages in that particular thread - that piece of information may shed light on what's going on.
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