This column has benefitted from a bug (automatic type conversion) that was corrected in 13.0.55.
We now need to explicitly convert the string to an integer and change the code accordingly:
yy = RegEx(name,".*?(\d+)\.(\d+)\.(\d+).*?","\1") As int;
mm = RegEx(name,".*?(\d+)\.(\d+)\.(\d+).*?","\2");
dd = RegEx(name,".*?(\d+)\.(\d+)\.(\d+).*?","\3");
if (yy<100) yy += 2000;
return (yy + "-" + mm + "-" + dd) As date;