Well, this was what I would do when the bug cannot be reliably reproduced and debugged: Dig through the forum, find out when the bug was reported the very first time and investigate the version control system or if this doesn't exist hopefully existing backups what was changed compared to the versions before.
-- <https://forum.pspad.com/read.php?4,76932,78714> PSPad freeware editor https://www.pspad.com
