Qidi Tech first layer PLA problem

Hello
I'm new to 3d printing. Got a Qidi Tech I printer, have had good experience with it so far.

I am trying to print a new object with a raft, and during the very first layer it seems that there's a "wavy" pattern emerging.

Material PLA 1.75mm
Temp 200, bed temp 60
Using Slic3r

Things I tried:
- slow down the printing speed
- reduce the height of first layer
- increase and decrease bed and/or extruder temp

Please see images for the defect. It seems to self-propagate once it starts. Any ideas?

thanks