Version

3.2.31

Reproduction link

sfc.vuejs.org/

Steps to reproduce

Just add comments inside Transition and you can see it breaks by showing a <transition> can only be used on a single element or component error

What is expected?

The transition component should work as expected since comments are not real DOM elements.

What is actually happening?

Vue shows an error saying: can only be used on a single element or component

use transition-group instead. see sfc

@posva I tested this one on my PR of #5266, its not a duplicate.