Vue version

3.5.15 (older versions seem to have the same problem too)

Link to minimal reproduction

https://play.vuejs.org/#__SSR__eNp9kD1vwyAQhv8Kujmyh3aKrEptlaEd2qrNyIKcq0OCAXFHYinyfw/gfA1RNvQ+z8HLHeDV+2oXEebQMPbeKMYXaYVolkFZ0qydFcp7VKHECZBxLOpJqq9WCpr65gqYAVPr7L/uqg05m1445BkJreu9Nhi+fZ4jCXNRSGbKGLf/LBmHiLNz3q6x3d7JNzTkTMJPQMKwQwkXxip0yBNe/H3hkM4X2LtVNMl+AH+RnIm546S9RbtKtW+80vaj9y6wtt2SFgNjWsfpU7loNsfiS0hrfn/w9Wvdp+q5zEk7wngEt2yIww==

Steps to reproduce

Just open the Playground.

What is expected?

No error, successful hydration.

What is actually happening?

An error is thrown.

Failed to execute 'replaceChild' on 'Node': parameter 1 is not of type 'Node'.

Any additional comments?

I confirmed this also fails in Nuxt, not just in the Playground.

Without the appear prop there's still a hydration problem, but not the explosive error.

The <slot /> isn't required, it also fails if the <Transition> has no content, but I think a <slot /> is more realistic.