My 92 300Ce Does this, so does my dads 1994 SL600. when its cold it stays in first gear. then when warmed up enough, it goes back to normal 2nd gear starts.
At least this is what I have noticed.
'92 300CE - Sold
2004 C240 - C7 Wheels
2015 ML350 - P1, Pano, Ash poplar wood, Sport Dinamica interior, Running Boards Keyless go.