so I tested using sub getOneRow, which works as expected, proving the dereferencing is correct.

Unfortunately not. In each sub you are not pushing a hashref onto the array (as you should) but instead pushing a hash, so the array essentially becomes the hash. To fix, in your subs push the hashref on:

push @data, $rowref;
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and in your calling routine iterate over each hashref rather than hash:

foreach $row (@data) {
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Otherwise, please investigate placeholders now before little Bobby Tables comes to tea.