Duplicate entry '2' for key 'PRIMARY' SQL=INSERT INTO `#__ucm_base` (`ucm_id`,`ucm_item_id`,`ucm_type_id`,`ucm_language_id`) VALUES ('2', '4692', '1', '0')

[Webdongle Elgnodbew]

Bug or not ?
https://forum.joomla.org/viewtopic.php?f=706&t=948473

Joomla update >>> reinstall core files ... doesn't fix
3rd party Template ruled out
3rd party extension ruled out.

It does actually save any changes to the article content but does not attach the tag to it.

Also fails to create tag from inside the Article

I am only using tags with core articles, no other instances such as categories, contacts or 3rd party extensions.

I also tried typing a different unique word directly into the tags box - usual behaviour it creates and associates that tag. The article saved without throwing any errors but when I reopened the article there was no tag and it had not been created in tags either.