Are you posting by email or from a mobile?

I've been having a strange problem with one of my WordPress blogs, and I haven't found any other topics on the subject.

It only happens when I create or edit a post. The words will reach a certain post halfway across the window and then paragraph break back to the beginning. So it looks something like this:

"Things have been picking up here
on the Island, so here's a few
announcements to catch everyone
up to speed: a fellow BU classmate,
and I have started a blog devoted to
the movies called Beyond the Backlot.
We'll be writing for it for the rest of the
summer and hopefully into next year
about the current cinema, trends in
the industry and classics you may have
overlooked that are worth the watch."

Once I publish the post it fits perfectly into the theme. This only occurs during editing or writing. It's getting a bit annoying that I can't format my posts in any way when for some reason the editor is making the margins super small. I've tried making it full screen, and I noticed that the kitchen sink will also only extend to the margin where the words are being cut off instead of all the way across the window.

There's nothing special in the code or any upgrades.

Any suggestions?