Back button not showing in a second page

Hi!
I dont know why but if i open my app and go to other page so i dont see the back button,
And if i tap on android back button the app is closes.
But if i tap on modal and after go to other page i see the back button.
Thanks!

someone? pleaseā€¦ :blush:

Can you give some more details, maybe reproduce this in a codepen?