i get the following warning when using proc boxplot

[VRD]

WARNING: Group variable values will be truncated to 32 characters.

WARNING: Formatted subgroup variable values will be truncated to 32 characters.

i get this warning when using proc boxplot.

symbol value=dot color=salmon;

   proc boxplot data=endp;

      plot rbw * treatlbl /

                     cboxes   = dagr

                     cboxfill = ywh;

            label  rbw = 'Relative Body Weight  change (%)';

   run;

[RW9]

Yes, I noticed this as well when I looked at this proc.  Probably a limitation in that procedure.  TBH I would change this over to use SGPLOT or GTL. 
proc sgplot data=xxx noautolegend;

  vbox aval / group=grp_var grouporder=data boxwidth=0.5 category=cat_var spread name="BOX";

run;

Or

proc template;

  define statgraph box;

    begingraph /;

      layout overlay /

        BoxPlot X=x_var Y=y_var/ _SortOrder_=Internal primary=true Group=grp_var spread=true boxWidth=0.5

      endlayout;

    endgraph;

  end;

run;