For example:
- Searching for #phorge.it_install returns tasks that are tagged with any of phorge.it install's subprojects (https://we.phorge.it/maniphest/query/.U7R4YMuWkkC/).
- However, searching for any(#phorge.it_install) only returns tasks that are tagged with the base phorge.it install project (https://we.phorge.it/maniphest/query/.MO.Xt84fFai/).
T15828: "Any" & "Not In" query operators should also involve project's direct milestones would resolve this issue for milestones.
Per T15828#22480 & comments after that one, it's potentially unclear/undecided how to resolve this inconsistency for subprojects.