MFD Prompting for fuel price after fillup

Until my last two fillups, every time I got gas, the MFD prompted me to enter the price I just payed per gallon right as I started the car back up - it came up automatically, and would disappear quickly on its own. Anyone have an idea of why this isn't happening now? Before, it happened every time I opened and closed the fuel door, but now, nothing, even after I have actually added fuel. To my knowledge, I haven't changed anything. If it isn't a setting I've changed inadvertently, could the switch that senses fuel door position be malfunctioning? I always keep the trip set to from start, and changing to trip a or b hasn't changed anything. I know I can update the price manually, but the automatic prompt was a killer feature.