Display Electronically switched 6 gears vary from A1 to M1

Peugegot 5008 BJ 2012 1.6 Diesel mechanical 6speed transmission electronically controlled. At the stand selector lever on A1 the display fluctuates sporadically between A1 and M1.But only sometimes.Sometimes in cold condition, sometimes after a certain driving time. Can someone tell me something about it. Thank you in advance Raider 58