Ours did that once, all we did is lower and raise the jacks again. One of the jack senors was stuck. Has not happened again. Our procedure is unhook everything, start engine and wait a few minutes for the air to build up, (yes the jack alarm will go off for a minute) raise jacks and then wait a minute or two for the air bags to fill. the leveling system will lift tires off the ground, however we don't like to so a few boards under the tires make us feel beter, never lift the back off the ground, that's your brake to keep you from rolling and bending your jacks.
2011: 54 days, 2012: 218 days, 2013: 175 days, 2014: 196 days
2015: 188 days, 2016: 72 days,
2009 Berkshire, 390QS, and toad