BUG #17745: RETURNING after INSERT does not return the same structure of response

The following bug has been logged on the website:

Bug reference:      17745
Logged by:          Paweł Podgórski
Email address:      pawel.jan.podgorski@gmail.com
PostgreSQL version: 14.5
Operating system:   Windows 11
Description:

When I try to "INSERT INTO .... RETURNING (channel)" the output is:
   channel
--------------
 3o0mNjcS4CMr
(1 row)

But RETURNING multiple attributes produces another output: 
"INSERT INTO .... RETURNING ( channel ,  last_processing_timestamp,
last_successful_processing_timestamp )"
                                     row
--------------------------------------------------------------------------------
 (3o0mNjcS4CMr,"2023-01-11 12:01:40.016988+01","2023-01-11
12:01:40.016988+01")
(1 row)

The output that is expected is similar to:
"INSERT INTO .... RETURNING channel ,  last_processing_timestamp,
last_successful_processing_timestamp "
   channel    |   last_processing_timestamp   |
last_successful_processing_timestamp
--------------+-------------------------------+--------------------------------------
 3o0mNjcS4CMr | 2023-01-11 12:01:40.016988+01 | 2023-01-11
12:01:40.016988+01
(1 row)