[atlas] Strong doubts about the option "DNS recursion"

I fear that the option "recursion_desired"
<https://atlas.ripe.net/doc/measurement-creation-api/> does not work
as expected. Here was my experiment. I registered a new domain name
which never appeared before,
d7b16b2a97627e8ccbcccf93e773ec3f.cosmogol.fr. Because of its
unreadability, there is zero chance it has ever been in a DNS cache. I
then ask Atlas probes to dig it, with "recursion_desired" set to
false:

{'definitions': [{'query_class': 'IN', 'use_probe_resolver': True, 'af': 4, 'query_argument': 'd7b16b2a97627e8ccbcccf93e773ec3f.cosmogol.fr', 'query_type': 'TXT', 'type': 'dns', 'is_oneoff': True, 'recursion_desired': False, 'description': 'DNS resolution of d7b16b2a97627e8ccbcccf93e773ec3f.cosmogol.fr'}], 'probes': [{'requested': 10, 'type': 'area', 'value': 'WW'}]}

But all the probes got the content of this TXT record! Measurement
#1034372 if you want to check (unfortunately, this parameter is not
displayed in <https://atlas.ripe.net/atlas/udm.html?msm_id=1034372>).
It seems wrong, they should all have retrieved an empty answer (here,
with dig, the behaviour I expected):

% dig +norecurse @MYSERVER TXT d7b16b2a97627e8ccbcccf93e773ec3f.cosmogol.fr

; <<>> DiG 9.8.4-rpz2+rl005.12-P1 <<>> +norecurse @relay1 TXT d7b16b2a97627e8ccbcccf93e773ec3f.cosmogol.fr
; (2 servers found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 33141
;; flags: qr ra ad; QUERY: 1, ANSWER: 0, AUTHORITY: 8, ADDITIONAL: 21

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags: do; udp: 4096
;; QUESTION SECTION:
;d7b16b2a97627e8ccbcccf93e773ec3f.cosmogol.fr. IN TXT

;; AUTHORITY SECTION:
fr.			165392 IN NS d.ext.nic.fr.
fr.			165392 IN NS d.nic.fr.
...