hmr bug: data-v attribute is not append on first item

[sibbng]

Describe the bug

I have a SFC with scoped styles. I have a array. In template I'm iterating this array on transition-group. Initially this array is empty. I'm pushing items by clicking a button. After first push the data-v attribute is append on first element. But when you keep adding element, first element is losing its data-v attribute and scoped styles are not being applied. Same issue occur when array have only one item initially. If array have more then one item initially, there is no problem. This is only happens in dev mode, after build there is no problem.

Reproduction

https://github.com/sibbngheid/data-v-bug

System Info

• vite version: vite v1.0.0-beta.11
• Operating System: W10 WSL
• Node version: v12.16.3
• vue 3.0.0-beta.15
• @vue/compiler-sfc version 3.0.0-beta.15

[underfin]

It's a bug with vue core, not vite.Please track in this.vuejs/core#1561