Since this is a feature that I never use on my travel routers, and it sends out large numbers of ping packets, which is something I really do not want my routers doing, I always just remove it using ssh and the command:
opkg remove mwan3
If you look through past posts in this forum, you will find multiple people have complained for various reasons that mwan3 should have a setting in the main GL iNet GUI to turn it on/off and it should be off by default.