When losing and then getting the focus, the terminal state gets messed up.

In the normal ubuntu terminal (ubuntu desktop 16.04).
You start vim, add some text, issue CTRL+Z, you drop into shell, issue fg, you continue vim as nothing happened.

In the ubuntu-touch (device:meizu pro 5 OTA-11, but I had it on my old nexus 4 OTA-10 also) terminal app.

If I do the same steps then I get the same result.

BUT, if I switch to another task, the vim job gets suspened (as if issued CTRL+Z), but when I issue fg then vim will not redraw the terminal and the terminal remains in some kind of raw mode (up/down/left/right keys will just echo the escape code to terminal and not move the cursor).