Slow web apps when launched in full screen mode from the home screen on iOS

We have a web app that will launch in full screen mode on iOS when bookmarked to the home screen.

The web app is significantly slower compared to running in Safari as normal.

I'm aware of some old articles on this issue like here:

http://ift.tt/2x3PyvV

Can anyone add updated information to this issue? Why does it happen? Is there a way around it?