### Vue version 3.6.0-alpha.2 ### Link to minimal reproduction https://play.vuejs.org/#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 ### Steps to reproduce Observe that in initial state (vapor mode active), the comment is considered as the content of the slot. If `vapor` is removed from the components, the comment is not considered and the fallback content is rendered. ### What is expected? A slot content containing only comments should trigger the fallback content to render. ### What is actually happening? The comment is considered as the slot content in vapor mode, resulting in the fallback not being rendered. ### System Info ```shell ``` ### Any additional comments? _No response_