This fumble stat is a pretty illusive one to track down. The best that I could find is that Taylor had 16 fumbles on the year and lost 8 of those. First in the nation for fumbles and tied for first in fumbles lost.
Just off the top of my head I know 2 of those fumbles were in passing situations when he go hit while he was in a throwing motion and lost the ball. If you drop those 2 he's tied with Ameer and others for 6 lost on the year (Ameer had 8 total fumbles). That's one more than Braxton Miller and Marcus Mariota (both with 8 fumbles) the best mobile QBs I can think of other than Manziel, who I can't find stats on but I don't think he turned it over much.
*I guess I forgot Robinson 6 total 3 lost for his short 2012 season, he's more of an interception machine though.
So in summary yes it's a problem, but it's really not something most other mobile QBs are immune from either. Ameer's stats are pretty high for a running back though, that is more of a concern to me.