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If you're using a wi-fi adapter and experiencing this problem, then I'm not sure how to help. But if you're using integrated wi-fi like I am (e.g. on the RPi 3) then to fix it, I just removed the first two lines under '# WIFI settings' in the code imported from interfaces.txt & also removed everything under the '# adapter handler' section header.
I also didn't import the two lines of code above the '# WIFI settings' header since it was already included in the network interfaces file.