refetchOnWindowFocus not working anymore in 'production' environment

[fillon]

Describe the bug
refetchOnWindowFocus not working anymore in 'production' environment

To Reproduce
https://codesandbox.io/s/github/tannerlinsley/react-query/tree/master/examples/focus-refetching

• when using npm run dev => refetchOnWindowFocus is working (and react-query-devtools enabled)
• when using npm run build / start => refetchOnWindowFocus is not working, react-query-devtools disabled which is normal for production

versions
"react-query": "^2.22.0",
"react-query-devtools": "^2.4.7"