Yes, it's bugged. Kind of glad it is though. Was running to BRF and came across a group of alliance and was able to out run them thanks to the bug not slowing GW down.
There is definitely a bug with it. At blackhand I noticed if you jump left-to-right, right-to-left you will stay at 200% speed. I'm assuming it's thrnglyph that is bugging as it jumps from 110 to 200. I thought it might have been from something blackhand was doing with those melting pots, but it seems it's s bug.