I've heard in several places now that people could not get connected to WiFi unless the moved the Country setting to come before their "network" section. Mine works just fine on a Pi 3B with the Country setting in the default location (near the end of the /boot/octopi-wpa-supplicant.txt file).
It's interesting to note that the older versions of OctoPi had the Country setting at the top of the /boot/octopi-wpa-supplicant.txt file (a lot of people never saw this in the older versions, since they used the octopi-network.txt file to set up their network).
Still, I'm not sure why it would matter. The settings in the octopi-wpa-supplicant.txt file are just linked to the wpa_supplicant.conf file in a directory on the other partition. The information is copied over on boot-up. I would not think the order it is listed in the /boot/ partition file would make a big difference. But then I'm no guru in how this actually happens.
If @foosel or @guysoft confirm that this could make a difference, I'll add a note to the WiFi troubleshooting guide.