# Is this weird pattern in my Martingale Residuals plot normal?

I'm running a cox model:

coxtest<-coxph(Surv(time=Age_Sample,time2=Age_event,event=LungCancer)~Cigarettes_Lifetime,data=mydata)


Then I do

plot(residuals(coxtest,type="martingale"))


And I obtain this weird plot:

Is that normal to have this shape? Or I have somthing wrong in my data? When I look on some internet examples, they all have a "scatterplot" and not just 2 lines of points.