Link to minimal reproduction

https://sfc.vuejs.org/#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

Steps to reproduce

just toggle that comment // objj.age++; and see how reactivity behaves, when this line is commented (disabled) yes nested props are not reactive but when this line is active object behaves just like any reactive object

What is expected?

i expect that nested props don't change in a shallow reactive object root elements only can be reactive

What is actually happening?

nested props also has some reactive behaviour

System Info

No response

Any additional comments?

No response

This comes up regularly. Re-renders caused by one reactive change will still update the whole template with the latest data, regardless of that other data being reactive or not.