Mine has done this a couple of times after being in 4 LO, can't replicate either, I just played around shifting into 4 HI - 4 LO and after 15 -30 seconds it worked fine in 4 HI. Annoying but until it starts doing it consistently or predictably I'll leave it alone.
2013 JKU Rubicon - Commando and 71 Jeep CJ5 (pretty much stock)
Teraflex 2.5" spring lift, Teraflex monster front and rear trackbars, G2 wheel adapters, Goodyear Wrangler MTR Kevlar 35 x 12.5 x 17, Superchips Flashcal, Warn Zeon 10, Smittybilt XRC bumpers front and rear with tire carrier, Metal Cloak Overland Fenders, Uniden Bearcat 980, Homemade side rails. 50" and 20" light bars and brackets.