If a plural property is mis-spelled as singular, then the routine tries to convert the PDL object into a scalar, leading to string conversion. This happened to me when I misspelled "colors" as "color", giving a terribly cryptic error
Argument "[8380065 8379300 8364510 8374200 8.37815e+06 8.36974e+06..."
isn't numeric in subroutine entry at .../path/to/.../PDL/Drawing/Prima.pm line 1420.
If a plural property is mis-spelled as singular, then the routine tries to convert the PDL object into a scalar, leading to string conversion. This happened to me when I misspelled "colors" as "color", giving a terribly cryptic error