I also ran into this problem with 11.1. After pulling some hair I decided to use Reflector and luckily understood that this has to do with a Browser settings level. Turns out that UltraWebGrid's Browser property is Auto by default, which causes IE and FF to render as if the BrowserLevel is "UpLevel" whereas Chrome renders with a BrowserLevel of "DownLevel". Funny enough, according to the docs "DownLevel" means the following: "Down-level browsers with an emphasis on compatibility with older standards and platforms with limited rendering capabilities", which basically means that IG sees Chrome as a DownLevel browser for some reason...

Anyhow, setting the Browser to "UpLevel" rendered the grid correctly and solved the problem for me, at least so far.