Custom Web Elements/Components receive undefined instead of false on subsequent re-render

[Maxim-Mazurok]

Vue version

3.4.31

Link to minimal reproduction

https://jsfiddle.net/uwegz5y8/23/

Steps to reproduce

1. Load repro
2. See Boo: false; typeof: boolean - as expected, because boo attribute is not set
3. Click "Toggle Boo"
4. See Boo: true; typeof: boolean - as expected, because now boo attribute is set
5. Click "Toggle Boo" again
6. See Boo: ; typeof: undefined - unexpected, since boo attribute is removed - we expect to receive false just like in the 2nd step previously

What is expected?

false

What is actually happening?

undefined

System Info

No response

Any additional comments?

This is similar to #10324, which was not actually a duplicate of #9006

b49306a didn't fix the issue. All it did was to change null to undefined in the 6th step of the original issue reproduction.

Kinda related to #9697

[linzhe141]

playground

[yyx990803]

fixed in 506c4c5

[Maxim-Mazurok]

Does not reproduce anymore with 3.5.0-beta.1 (https://jsfiddle.net/gu3rx7ed/)
Thank you!