I am able to reproduce the problem. But it is most likely because of the warning below. I'm checking if we can fix this.
WARNING: Console code page (437) differs from Windows code page (1252) 8-bit characters might not work correctly. See psql reference page "Notes for Windows users" for detail
I installed pgAdmin 9.8 on Windows 10 to teach a class. the query tool, etc. seem to work well, but plsql tool shows a strange message, and commands like \d seem to hang