That's very odd indeed. I'd make sure that you have javascript enabled, but beyond that, I'm not sure why the two same browsers would display the data differently. Does the rest of the site render the same?
What I have discerned so far...
If the browser is freshly opened and I have an alert, it displays as normal. If I refresh the browser and have a new alert, it is stretched full width and at absolute bottom. This just started happening about 3 days or so ago