Randomly when I receive a text and then send a reply and receive another text from the same person. The response I get back from the person will show up out of order. Usually the end result will be their two SMS messages in a row and mine showing up last.
The text messages in a thread will be displayed in order of the time they were received and sent. However, depending on the time zone of both phones this might not work correctly at times. Make sure both your time zones are set correctly.
If this doesn't resolve the issue, reinstall the software with Nokia Suite and check if this makes a difference.
Please keep me updated on your progress so that I can investigate further, if necessary.