strange behavior of @ in tag searches

[Victor A. Stoichita]

Hi,

I’m a bit puzzled by the behavior of the agenda search when tags 
have hierarchical structure and start with @. I attach two 
minimal examples.

In testfiles.org I have:
--8<---------------cut here---------------start------------->8---
#+TAGS: [ @anthro : bib ]

* my anthro 
 task                                               :@anthro:
* my bib 
 task                                                      :bib:
--8<---------------cut here---------------end--------------->8---

I restrict the search to the buffer and search for the tag 
"@anthro".
I would expect to get the two headings "my anthro task" and "my 
bib task".
Instead, I only get "my bib task".

Now in testfiles2.org I have:
--8<---------------cut here---------------start------------->8---
#+TAGS: [ anthro2 : bib2 ]

* my anthro2 
 task                                              :@anthro2:
* my bib2 
 task                                                     :bib2:
--8<---------------cut here---------------end--------------->8---

Notice that here the parent tag set in the header does not start 
with @ while the tag on "my anthro2 task" starts with @.
When I search for "anthro2" (no @), I would expect to get only "my 
bib2 task". But here I get both headings.

Am I missing something? Does @ have a special meaning in tags?

This is with org mode version 9.4.3. 

Regards,
Victor

testfiles_2.org
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testfiles.org
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