- A user with flow-enabled User talk page creates a new page that is a subject for Review.
- Another user reviews the new page via Special:NewPagesFeed and clicks on Review icon - the following message is displayed: "An error occured while marking the page as reviewed. Direct editing via API is not supported for content model flow-board used by User_talk:Etonkovidova"
The page, in fact, gets reviewed and a correct Notification is sent and displayed.
Users with wikitext User page do not have that error displayed when their page(s) get Reviewed - a template is added, e.g. {{subst:Db-notice-multiple-NPF|Mavetuna58 1}}