Failed to execute 'insertBefore' on 'Node'

[ropeladder]

Vue.js version

2.0rc3 (probably was occurring in 1.x versions but I'm not sure)

Reproduction Link

https://jsfiddle.net/7e0sfqo7/

Sorry it's not very minimal. Had a hell of a time reproducing this.

Steps to reproduce

Click "Change Data" button.

What is Expected?

New data will populate template.

What is actually happening?

Firefox: "NotFoundError: Node was not found"
Trace:
insertBefore()
updateChildren()
patchVnode()
updateChildren()
patchVnode()
patch()
lifecycleMixin/Vue.prototype._update()
lifecycleMixin/Vue.prototype._mount/vm._watcher<()
get()
run()
flushSchedulerQueue()
nextTickHandler()

Chromium: "Uncaught NotFoundError: Failed to execute 'insertBefore' on 'Node': The node before which the new node is to be inserted is not a child of this node."

I'm assuming this is related/similar to #3043.

[jddy]

I also met

[ktsn]

The error is caused by <br> on line 363. It works when I remove it.
But looks like this error has more complex cause because it may work when I remove the other parts. 😕