And replying to myself:
The problem seems to be that some if-clauses in `org-entry-properties'
are not right:
- when requesting the ALLTAGS property, the code that adds its value
to the alist did not check if the variable `specific' is
"ALLTAGS", but "TAGS"
- when requesting the BLOCKED property, the code that adds its value
to the alist did not check if the variable `specific' is
"BLOCKED", but "TAGS"
So requesting one of those properties explicitly didn't work.
I attached three patches for org.el. Patch 0001 fixes a type in the
docstring of `org-entry-properties', patch 0002 modifies the if-clause
for the ALLTAGS property to check if `special' is "ALLTAGS" and patch
0003 modifies the if-clause for the BLOCKED property and adds BLOCKED
to the list of properties that are excluded if user requests all or
standard properties.
Hope I got it right and understood the logic in this function.