I have started using canary version 3 now on Mac OS as well on my working laptop on window. On both operating systems I can observe the following behavior.
When writing a text and put directly below a list item (“-”) the text above becomes h1. Additionally the list item character sticks to the new line which was not the case in version 5.9.
It is expected as well.
You can remove the list bullet by hitting enter again.
Markdown allows inserting a blank line between list items to split the lists.