Major Description
Joins can fail with an out-of-bounds access to fields that are not referenced in the script when records without schema (including all variable-length records) are involved.
Example by Ben Reed:
i1:
1 c D E
1 a B
i2:
0
0 Q
1 x z
1 a b c
i1 = load 'i1';
i2 = load 'i2';
j = join i1 by $0, i2 by $0;
dump j