I'm not sure if you meant to tag me, I'm no expert, but I'll try to help. Sorry for the delay, it's been a crazy week.
This is my interfaces file:
This is assuming you have the same setup as me, the EB3 with the external WiFi dongle attached. I set mine up to use the internal WiFi (wlan0) to connect to the internet, while I ssh into Erle directly through the external WiFi (wlan1).
Did you remember to change the static entry in the interfaces file to wlan1?
Also, in both /etc/hostapd/hostapd.conf and /etc/dnsmasq.conf files, change the first non-commented line to wlan1 so that it reads "interface=wlan1".
Make sure to reboot EB3 afterwards.
For reference, when typing "sudo systemctl status hostapd.service" I get: