### Vue version latest ### Link to minimal reproduction https://play.vuejs.org/#eNqFUM1KxDAQfpUhCG1BNvealhXxJLiggpdcajorwTQJybQiy767ky3Kspe95Zt8fzMHcR/jZplRtEJlk2wkyEhzBDf4z04Lylr02tsphkTwEKYI+xQmqDaygCKttDfBZ4LgDUIHdQNdD4PDRLUWZahFc6e9kmsA2zEgnKIbCBkBqOJVHgDbIuDgVbfOJJOUPFMwzPTjELIJEceerQvkH3Er/npdWWnEvfX4OFnK6lByamzhv28LS7Ajtz729bXyo13AuCFnNv9OQ4yYTgmluvqYiYKHrXHWfDHhBjmxrkpM1TDtdLTn3Ru8716eXpVc+auxZOfL1cXxF12okng= ### Steps to reproduce open the link ### What is expected? no error ### What is actually happening? get error: `Cannot read properties of undefined (reading 'toLowerCase')` ### System Info _No response_ ### Any additional comments? Issue exposed by #8334 and doesn't seem to be fixed by #8338
Vue version
latest
Link to minimal reproduction
https://play.vuejs.org/#eNqFUM1KxDAQfpUhCG1BNvealhXxJLiggpdcajorwTQJybQiy767ky3Kspe95Zt8fzMHcR/jZplRtEJlk2wkyEhzBDf4z04Lylr02tsphkTwEKYI+xQmqDaygCKttDfBZ4LgDUIHdQNdD4PDRLUWZahFc6e9kmsA2zEgnKIbCBkBqOJVHgDbIuDgVbfOJJOUPFMwzPTjELIJEceerQvkH3Er/npdWWnEvfX4OFnK6lByamzhv28LS7Ajtz729bXyo13AuCFnNv9OQ4yYTgmluvqYiYKHrXHWfDHhBjmxrkpM1TDtdLTn3Ru8716eXpVc+auxZOfL1cXxF12okng=
Steps to reproduce
open the link
What is expected?
no error
What is actually happening?
get error:
Cannot read properties of undefined (reading 'toLowerCase')System Info
No response
Any additional comments?
Issue exposed by #8334 and doesn't seem to be fixed by #8338