Thank you for sharing your detailed approach @lays 
The images and thoroughness is helpful and greatly appreciated!
However, this is ultimately still leaves us without a definitive, reliable and explicit answer to the question.
My current approach is to infer the type based on the board name prefix “Subitems of”, but as mitko-slapdash pointed out, placing reliance on this could be problematic. In both cases, yours and my approach imply an uncertain answer, rather than giving the explicit answer I am after.
Regarding the existence of a “phantom” item, this only raises further questions. Instead of resorting to the use of one undocumented feature to resolve ambiguities in another undocumented feature, Monday should be able to give us an explicit answer to the question above.
