cannot delete a short cut designated for an input syste

it seems that I desginated a short for the one of the language input, but i want to delete it, yet i cant find anyway to do so. (see below)

i located this language input but there is nothing i can change the short cut here.

i also went to shortcut session of "input sources" but there simply isn't this short cut. i cant even delete it. please help. this shortcut is disrupting my typing and writing seriously.