Aggresively Switches from 4G/3G to Edge

Hi. I've experienced this for a while and I kind of got used to it but I just want to know your opinion regarding this. First off, I'm from the Philippines using a Globe telecom sim. Whenever I use data, I've noticed that it switches to E from 4G/3G quite aggresively. I have a spare phone on the same network and it remains on 4G/3G. To remedy this, I need to turn off the mobile data, go to Network Operator then choose 'Select Automatically'. I go to Network Operator again but this time choosing the network I'm on (Globe). After some time, it'll go back to E then I have to repeat the process again.

Is this a modem issue or a network issue? I'm on modem OE8, running Albe S6 Port 3.5.