I have a problem with the LNAV Light after takeoff. When i press the TO/GA knob and i rotate and after 400ft i activate the AP then is the VNAV light on and the LNAV light off. The LNAV and VNAV is activated and ARM before takeoff. The Airplane is following the route correctly. What is the Problem?

I have a problem with the LNAV Light after takeoff. When i press the TO/GA knob and i rotate and after 400ft i activate the AP then is the VNAV light on and the LNAV light off. The LNAV and VNAV is activated and ARM before takeoff. The Airplane is following the route correctly. What is the Problem?

Same happens with the -800/-900. The goes out as it should after TO/GA pressed, but stays out. LNAV/VNAV still work perfectly fine, but to get the light to come back on, you have to re-select LNAV.