That is interesting. I upgraded one EX3200 to the same release, but I didn't see this message.
Although the motd should come before you get the software release on the switch(the other way as you are seeing), is it possible that someone configured "set system login message" before the upgrade?
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If this worked for you please flag my post as an "Accepted Solution" so others can benefit. A kudo would be cool if you think I earned it.