Strange behavior of Foldable (,) a

The definion of Foldable (,) a is as follows.

instance Foldable ((,) a) where
    foldMap f (_, y) = f y
    foldr f z (_, y) = f y z

I am very confused with this definition. As a consequence, we have

maximum (1,0) == 0

I believe this is not something we want.

Trac metadata

Trac field	Value
Version	8.0.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Core Libraries
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CC	ekmett
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Architecture