G'Day Oh Wise Ones

I come to ye with some great confuzzlement. I have a loop like so:

for (my $i = 0; $i < scalar(@array); $i++) {
    for (my $j = $i; $j < scalar(@array); $j++) {
        foreach my $value (@{$hash{$array[$i]}{$array[$j]}}){
            # do great deeds
            }
        }
    }
[download]

This loop does crash. And, it is apparently the foreach that is causing the crash, as this still crashes:

for (my $i = 0; $i < scalar(@array); $i++) {
    for (my $j = $i; $j < scalar(@array); $j++) {
        foreach my $value (@{$hash{$array[$i]}{$array[$j]}}) {
            next();
            # do great deeds
            }
        }
    }
[download]

But importantly this does not crash:

for (my $i = 0; $i < scalar(@array); $i++) {
    for (my $j = $i; $j < scalar(@array); $j++) {
        next();
        foreach my $value (@{$hash{$array[$i]}{$array[$j]}}) {
            # do great deeds
            }
        }
    }
[download]

I should be clear: the data structures are exactly as presented. @array is a simple array, while %hash is a hash of hashes of arrays. This HoHoA is really a DBM::Deep object, however, as I had expected this to be more efficient on memory usage.

I should also point out: this code works properly with smaller datasets, but not with my full dataset, which includes millions of data-points in the HoHoA and tends of thousands in the arrays.

In my simple-minded view this indicates a memory-leak in the foreach loop. Am I missing something? In general, should I be doing something different rather than a foreach? Or am I vastly confuzzled and missing something obvious to ye great and mighty ones?