It keeps happening to me today very frequently. Tell if i can enable some log, or look into a log that could help you.
Last time it happened was when i removed the line with the character, replaced it with the correct bracket, saved the file. Then switched the window to run the script. When i came back to PSPad the line was replaced with the character again. Btw. its not just a character, then line has more than 500B. -- <https://forum.pspad.com/read.php?2,75694,75780> PSPad freeware editor https://www.pspad.com