I've noticed that for open shadow dom, the contents of the shadow dom are properly traversed except slotted items are not, however if the shadow dom is closed the contents of the shadow dom are not traversed but the slotted items are.
Hi @jlandrum, thanks for raising this. For now I've decided to no work actively on the project until I find a sponsorship. I will keep this issue open so when I get back to the project I will remember about it :)
I've noticed that for open shadow dom, the contents of the shadow dom are properly traversed except slotted items are not, however if the shadow dom is closed the contents of the shadow dom are not traversed but the slotted items are.
The open behavior can be seen here: https://lit.dev/playground/
I couldn't find any examples of closed as it's uncommon but the behavior is interesting and may be related.