I am going to read your mind and say that this site is eityher one that has been upgraded from joomla3 unsuccessfuly or that you have copied articles directly from another site using the database. It is reproducible on articles that were created in this way but not reproducinle on any new articles created in joomla 4

Is that correct

The website has been upgraded from Joomla! 3 to Joomla! 4.

Articles are not being copied from another website; they are being copied within the website.

I have not been able to reproduce the error when creating copies of new articles created in Joomla! 4.

The error usually occurs - but does not always occur - with errors created before the website was upgraded from Joomla! 3.

So basicaly I have guessed correctly. The upgrade from 3 to 4 was not completed successfuly as it should have created a record for each article in the #_workflow_associations table. (even if you are not using workflows it needs a record in that table). Newly created articles in j4 have that record created automatically which is why you didnt have a problem with those.

The sql query below should create the missing records for you.

replace #_ with your own db prefix

INSERT INTO #__workflow_associations (item_id, stage_id, extension) 
SELECT c.id as item_id, '1', 'com_content.article' FROM #__content AS c 
WHERE NOT EXISTS (SELECT wa.item_id FROM #__workflow_associations AS wa WHERE wa.item_id = c.id);

After running that query it should tell you that a cumber of records were inserted.

If it says 0 records were inserted then its a different problem

Thanks for the suggestion.

I ran the following query (our prefix is j17_):

INSERT INTO j17_workflow_associations (item_id, stage_id, extension) 
SELECT c.id as item_id, '1', 'com_content.article' FROM j17_content AS c 
WHERE NOT EXISTS (SELECT wa.item_id FROM j17_workflow_associations AS wa WHERE wa.item_id = c.id);

But it had no effect:

0 rows inserted. ( Query took 0.0080 sec )

I also checked j17_workflow_associations and records do exist corresponding to the article IDs that I am unable to copy.

-Eddie

ok - seemed a good guess as its a fairly common error

I have got the exact same problem. When saving with save as copy the new article is created in com_content, but not shown in backend. The article that I copy from HAS got an entry in the #__workflow_associations table.