most likely the 2" lift is whats causing the axle to pop.Seems the passenger side is the one that pops out the most due to the front diff not centered in the bike.
I highly recommend using a liberal coat of anti-seize on the splines before re-installing the axle. If you ever have to remove it, you can thank me then.pull the axle out an spray the spines in the diff with brake clean an clean the groove out probly trash in it ive had it happen before just took some proper seatin push it in an pull out until it locks in good mine is a 14 with low miles had his problem with factory replacements
Yes, they are longerI have gotten a new clip and installed it so far so good it hasn't pulled out ? r the rhino axles any longer to help prevent this