Version

3.0.0

Reproduction link

https://codepen.io/l1shu/pen/PozMyJM

Steps to reproduce

1: Open codepen link 2: Find checkbox used v-model doesn't work with reactive variable 3: But it works with a ref variable

What is expected?

reactive and ref all work

What is actually happening?

only ref work

See #2700 - unfortunately this will be considered a usage caveat for now, since v-model by design always replaces the original value, so use of a ref or a nested object property (e.g. v-model="state.foo") is required.