Type error in v-for on Object with key and value

[Snack-X]

Vue version

3.5.12

Link to minimal reproduction

https://play.vuejs.org/#eNp9UctOwzAQ/JWVL1CppILCpUorAeoBDoCAG0YoTTdpWse2/AhFUf6dtaOUHlBvnt3Z2dlxy261ThqPbMZSh7UWmcMFlwCphuaiUGbOWZMJj2PY4Q9UEtRqy1mkALQtFEqdU2cEXTcLOJIJRI2JJmI6ORImaHNTaQcikyWJO8sZWHQ+UHMlrQsbSAo+SHYG1plKlp/DAzqYQxvEsxmcZUJvsrNxgCuCK3QR0XIuCy9zVykZHTbD/KgfNrTQSGgiN530lhZsTHbIQ1GVydYqSaFENme5qnUl0DzrIEmWyWAfAWeZEOr7MdacoaCGer7BfPdPfWv3ocbZi0GLpkHODj2XmRJd316+PeGe3odmrdZeEPtE8xWtEj547Gl3Xq7J9hEvun2otTKO4ni3y71DaYejgtHA7CKfvt7j/YnT/+xOk+s4R4FSil8NmqBJAU6Tm+TyinW/1cjLDA==

Steps to reproduce

Using v-for="value, key in someObject" on someObject: { [key: string]: string } produces type on key

What is expected?

Type of key should be string

What is actually happening?

Type of key is string | number

System Info

No response

Any additional comments?

According to the changelog, this should've been fixed in 3.4.28.

It feels like a regression of #8819, but changing the version of playground to 3.4.28 still has the same issue.

If I change the type of an object to Record<string, string>, the issue goes away.