How to correct element width display in responsive views?

I have trouble getting a group of input elements displaying correctly in responsive mode. It’s displayed good in all modes except “Ipad” mode. How do I solve this?

One element moves down a row. Considering how it looks, I’d much rather use the “stacked” mobile version also for Ipad size screens. Pls see screen shots below.

Signup page in 1200px

Signup page in 768px

Signup page in 667px