Vue version

3.2.45

Link to minimal reproduction

https://codesandbox.io/s/gifted-morse-xvs4s4?file=/src/App.vue

Steps to reproduce

Here's the same code working in the SFC Playground: https://sfc.vuejs.org/#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

What is expected?

The component v-model should be bound to and update the correct property.

What is actually happening?

Nothing.

System Info

No response

Any additional comments?

No response

In Vue 2, v-model requires a value prop and an input event - so that's what it also requires with the compat build (until you disable v-model compat).

So this works as intended.

As best as I can tell this also doesn't work which is why I ended up trying to update:

https://codesandbox.io/s/shy-cache-y6k0gz?file=/src/Child.vue

Fixed an issue and it does work in the sandbox but the same implementation doesn't reflect in the parent component in my app. Investigating further.

Also, fwiw, this seems to be the case for both examples if the whole project is set to MODE 2 or 3 and same at just the component level.