This is EXACTLY what the bike does with a sticky shift pivot bolt. The problem is when you donwshift once, the shifter has to return up to the resting position before you can downshift again. With a sticky pivot bolt, the shifter downshifts once but doesn't come back up all the way and can't downshift again. If you manually, get your toe under there and pop it up a bit, you can continue to downshift.
The quick fix out on the road is to spray the pivot with WD-40 or PB Blaster and move the lever up and down to lube the pivot. The longer-term fix is to remove the shift lever and lube the shaft. I've added this to my list of stuff to do at ever oil change.
Here's a good photo (posted by Checkswreks) of the part in question. The bolt on my 2013 had no lube on the pivot bolt at all and started sticking at only 2000 miles after a long weekend of dirt riding down in Yosemite. A shot of PB Blaster made it feel like new and some grease added when I got home has kept it from happening again.