That is G-Side random effect with SUBJECT_ID variable.
If you can get model convergency you need some skill to adjust parameters of model . Check this:
https://support.sas.com/resources/papers/proceedings12/332-2012.pdf in proc mixed, the random and repeated statements model G-Side and R-Side random effect separatedly.
Correspond to PROC GLIMMIX ,it should be:
G_Side effect:
random intercept / subject = Patient_ID;
R_Side effect:
random visit/ subject = Patient_ID residal ;
or
random _residual_/ subject = Patient_ID;