TL;DR: a task is both blocked and not-blocked according to queries. X ∧ ¬X ≣ true.

Allow me to describe the situation I have.

I have a query:

• project: XYZ,
• statuses: Open,
• blocked: Hide Tasks Blocked By Other Tasks.

And it shows up i.a. T57 on my Phabricator instance.

Then I change the query to:

• project: XYZ,
• statuses: Open,
• blocked: Show Only Tasks Blocked By Other Tasks.

And again, T57 is on the list.

T57 is blocked by T70 and T77 (and few others but those two are rather representative).

• T70 is Open. It was Resolved once, but then reopened.
• T77 is Resolved. It was changed once to Waiting and then back to Resolved.
• (those other tasks are all Resolved. None of them have any Blocked by tasks).

The Waiting is described in maniphest.statuses as:

"waiting": {
  "name": "Waiting",
  "transaction.icon": "fa-hand-stop-o"
},

Also, I have 3 maniphest.custom-field-definitions but they are not relevant I suppose? Other than that, this is a pretty vanilla instance.

Phabricator Version 7fd6704fb5c789be51757df3b4d8c43ce0fbc995
Arcanist Version 2db40f995337cb329d7c10b47fdbdbfb0c8e77e8
libphutil Version 610ca9eba906c2033cfe9b56c2007b2e555d5bf9