Hello, I have a 2015 Tallboy Carbon. 2x10 drivetrain, Shimano SLX M670 shifters, and Shimano XT front derailleur. Tonight as I was riding, after a couple of miles in I noticed all of a sudden I was unable to shift my front shifter. It just felt jammed. I finished the ride and looked at it when I got home and couldn't visually see anything broken. I noticed a x2 and x3 switch on the bottom of the shifter. It was set to x2 and I changed it to x3 it started working again. I'm just trying to figure out what the issue is since it should be set to x2. Do I need to adjust the limit screw?

Even though this bike is a 2015, it's fairly new, I bought it off Craigslist about a month ago and the previous owner had only ridden 3 or 4 times (I believe it the condition it is in). And I have only ridden it on the trail 4 times myself.