Scripted for loop string concatenation not working

[Per Östlund]

The following script:

i:="";
lst := {"Here ", "are ","some ","strings."};
s := "";
for i in lst loop
  s := s + i;
end for;
s;

gives the result

""
{"Here ","are ","some ","strings."}
""

""

s becomes empty instead of containing the expected string.

[Per Östlund]

Fixed in r20241.