Wall strange artifacts in a rail kossel

Need some help to identify these problem, in theses model its always getting these strange lines in the middle of the hole, the surface its a circle with a hole on the middle. I've re-printed the model it always getting these line pattern at same place. I thought might be a retraction problem I've start with 2mm now I use 1.7mm and I'm starting to get a lot of stringing. I'm have a bmg extruder mount on my kossel.

These is my configuration in marlin

#define DEFAULT_MAX_ACCELERATION { 4000, 4000, 4000, 10000 }


#define DEFAULT_ACCELERATION 1200
#define DEFAULT_RETRACT_ACCELERATION 4000
#define DEFAULT_TRAVEL_ACCELERATION 1200


#define DEFAULT_XJERK 10.0
#define DEFAULT_YJERK DEFAULT_XJERK
#define DEFAULT_ZJERK DEFAULT_XJERK // Must be same as XY for delta
#define DEFAULT_EJERK 20.0


In other models its not visible or its not a big a problem, but I also notice that I've some of these patterns in the internal wall