Hey Mr. OneOfone (Trevor)
Years ago I subscribed to "Electronics Australia" as well as "Australian Electronics".
They began to get ahead of each other as you descrbed US S&T. The situation became so bad that I was recieving June issues in March and July's issue in April.

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After some years of this the publishers eventually back tracked the issues gradually and order was restored.
I don't see any reason for this occurring. It seems to throw things out of whack.