If you hotspot have a fixed SSID, Key and channel, then you can hardcore this in the settings.

The config is in /etc/config/wireless. Once you fix the settings you can turn off gl_health program so that it does not detect and change your repeater settings.

/etc/init.d/gl_health stop
/etc/init.d/gl_health disable 

Usually you should have a fixed ssid and key, but if you use phone as hotspot, you probably cannot set the channel. Unfortunately for MT300N-V2 you have to specify the channel to connect. If you can fix the channel of you hotspot it should be good.,