I've found that premade comments are not working in 2.5.5 develop installation on php5.6. When I add new items, they do write to the database although nothing shows in the admin panel or in the order editor.

The best I can contribute is that I did a file compare and it looks like 2.5.5 develop branch is currently using the same code as 2.5.4 for ...admin/premade_comments.php

Maybe a mysql vs mysqli issue?