Wlan not starting at boot, even though it should be...

[char...@gmail.com]

Hello!  I have a Rev C Beaglebone Black with Debian that is experiencing some unexpected networking behavior.  My BBB has a USB Wifi dongle plugged into the USB port with the HDMI cape disbled, as well as the wifi-reset service installed and enabled.  Additionally, I sometimes use a LAN cable with eth0.

When I power on my BBB from the barrel connector with only wlan3 connected, the network interface doesn't come up at boot (can't ping or SSH).  However, if I then plug in eth0 while the board is still powered on, wlan3 comes up (with an IPv4 address), as does eth0 (IPv6 address).  Why might this be happening?  I would like wlan3 to come up regardless of eth0.

Here are the relevant sections from /etc/network/interfaces:

auto eth0
iface eth0 inet dhcp

#allow-hotplug wlan3 // tried with and without this line
auto wlan3
iface wlan3 inet dhcp
    wpa-ssid "<Local SSID>"
    wpa-psk "<SSID password>"

Thanks!