Does my ISP know which Distro I'm using?

Curiosity: I know websites and ISPs can determine what browser and OS you're using but do they know which flavor of that OS like Lubuntu, Kubuntu?

I ask because the process to activate my modem went through without a hitch in Ubuntu but didn't work in Bodhi Linux. It could have been because I wasn't using Firefox in Bodhi.

I'm using Bodhi Linux and my ISP is Comcast Xfinity by the way.