(I've never seriously used Haskell) I wonder if the strong static typing has something to do with that. That eliminates many if the common bugs found in Python programs.
Perhaps the nature of Haskell discourages changes, making the community more stable.
That would be the optimistic view. In reality, `NoneType has no attribute Foo` errors happen in production all the time.
And Python does have static analyzers, including for typing.
Could be because of extra flexibility those types grant you, but it's not about bugs.