WP Interface and theme has changed

Hello!
I have 2 problems
the smaller: I had the colors “sunrise” selected in my dashboard.
After upgrading to 4.2, the dashboard is always black and white. I can change the profile as I like, the colors remain so. Just annoying – but why?

the real problem:
I’m using twenty twelve and I have a childtheme. (I updated Twenty twelve, but that should have no effect on my Childtheme)
The font of the website I’m working on has now changed to times New Roman. I have checked the whole CSS up and down – nowhere exists Times New Roman as a font.
In addition, my code changed and I have no idea where this comes from, and how I get rid of it. I now have on each side an extra “header”

<Header class = “entry-header”>
<H1 class = “entry-title”> </ h1>
</ Header>

I did not find this in my child theme anywhere, but the code is there when I go over it with the inspector

Furthermore, also the text-font of the Metaslider is clearly no longer in the original font.

But if I look only to the design of my Childtheme under Themes, everything looks fine, like it should look like.

* despair*
Does anyone has an idea, what this could be and where to look for the error?

LG Birgit