Imagine that we have argument of boolean type. We make a typo - write "False" instead of "false". Parser consider it as "enum", not boolean. Finally we don't have an error - after processing we have "true" boolean value.
Input Coercion
When expected as an input type, only boolean input values are accepted. All other input values must raise a request error indicating an incorrect type.
Imagine that we have argument of boolean type. We make a typo - write "False" instead of "false". Parser consider it as "enum", not boolean. Finally we don't have an error - after processing we have "true" boolean value.
From spec: