They render as loose lists (note the ugly spacing that appears) regardless of the number of new lines between them:
https://imgur.com/VEiAZKV
The workaround is adding a tab (or other character, like a braille space) between the lists, which really makes them one list:
https://imgur.com/Z5WLy6w
If you have two lists separated by only new lines: https://imgur.com/IFejJvX
They render as loose lists (note the ugly spacing that appears) regardless of the number of new lines between them: https://imgur.com/VEiAZKV
The workaround is adding a tab (or other character, like a braille space) between the lists, which really makes them one list: https://imgur.com/Z5WLy6w
Which makes it render in a less worse way: https://imgur.com/F5lc0ek
This is expected behavior per CommonMark.