keyboard layout seems to have changed in some apps?

A few minutes ago I was typing a search in Chrome and I noticed the bottom row on my keyboard had changed -- to the right of the 'm' key was a dash where there used to be a parenthases like '.

I went to the email app and started to type an email and noticed the layout changes depending if you are typing in the address field or are typing the message..

However, while I'm typing this in this forum, the keyboard has returned to 'normal' and the parenthesis is back where it should be.

I've never noticed this changing keyboard layout before and I wonder what is causing it. ????