Tiup offline mirror "Error: decode key: invalid character '\x00' looking for beginning of value"

Question

I have got custom tar from pingcap using tiup mirror clone. I am able to install tiup using included local_install script. On linux box, the script confirms that it has set the mirror to my local dir. But when I do "tiup mirror show", it gives invalid char error.

$ tiup mirror show
$ Error: decode key: invalid character '\x00' looking for beginning of value