Yes. If the pulse lengths are not what you expect then anything can happen.
Those aren't snippets. It's an entire sketch. Run it on your Arduino, open Tools->Serial Monitor, and set the data rate to 115200. Look at the values displayed. With the stick centered, both numbers should be near 1500. The first number should vary from about 1000 (full left) to 2000 (full right) when you move the stick left and right. The second number should vary from about 1000 (full back) to 2000 (full forward) when you move the stick forward and back. Are they working as they should?