I suspected that, too. So I deleted the cache, set the resolution to 1920, started MP and the problem was still there.
By the way, the problem came up with default blue wide skin, too.
When you get there, worth checking what MePo thinks your display is - in Config GUI, look at General->Startup/Resume, it will tell you what your start screen is. I'm wondering, your listed clients are all laptops but you output is HDMI, so operating a 2nd screen I assume, this could be source of mismatch problem - windows and/or MePo getting confused.