Dynamic Racing Line

Hi. I've tried searching the forum but can't see my issue. 

I have dynamic racing line turned off. When I'm doing a time trial I get a light blue line on the track. Any idea how I remove it?  

I've tried switching racing line on and then I get the 'proper' line over the top of the blue line. Switching off then just leaves this dotted blue line. 

Thanks. 

Martyn.