Why each switch from Chrome and Open Others and back to Chrome Reload the Web again?

Does this Chrome issues or Moto G 2015 issues? We have Moto G 2015 1GB RAM 8GB ROM, each time browse using Chrome and open one or two pages... then switch to others app example Twitter or Facebook.. then back to Chrome Tabs this Page Reload again... what happen? does this Chrome issues or Moto G 2015 issues?

Another issues is, if we open new tab in Chrome the page not open in the background.. the website/page will be load when we switch to this Tab... does any clue about it?

Thanks

@jauhari
Moto G 2015 user