Thanks for your reply. I think you are close to the source of the problem, in it has to do with array sparseness or compaction.

What I found is that I have an AOA (with some sub-AOA's), and items are deleted or splice'd out. All the operations on the top @array look "simple", no ref's to routines or anything.

Yet when it came to removing the last item of an array by a splice (e.g. splice( @array, 0, 0) it seemed to work but later on I get the fault. If I instead put a check before the splice and did

if( scalar( @array ) > 1 ) {
  splice(@array,$i,0);
} else {
  @array = ();
}
[download]

the exception goes away.

I'm not sure that this is really solving the problem, or just pushing it elsewhere.

This script is old and has been working for eons (although only used a couple times a year). The incoming data naturally changes. However, strawberry perl itself does get updated and although I doubt it I'm wondering if something got changed in perl such that this is now showing up.

While trying to find a solution to this problem I did find this posting in PerlMonks from January 25, 2017 and I'm wondering if there is possibly some underlying cause (I do use HOH's and ENV items): http://www.perlmonks.org/?node_id=1180341