Anddem92

So I was on the trail tonight and I went into four low and a few feet down the trail after making sure it engaged and locked it kicked back into neutral and I'm not sure if this caused it but when it did it shattered my heater valve. It doesn't make sense to me as to why it would do that unless it was coincidence that both happened so I was lucky enough to get my granddad to tow me to napa which surprisingly had the valve in stock somehow so that's fixed but does anyone have any idea why it would jump out of four wheel like that? Is the linkage just not reaching back far enough? And if so how would I fix that I haven't done any work on a four wheel drive before as this is my first jeep