Page displays content correctly, but editor and database thinks it has 0 words

A site I am responsible for is correctly displaying text (and a picture) on its home page (set up via Settings / Reading / Front page displays / Static).

However when I try to edit the page in the editor, it reckons it is blank and contains zero words, whether I use the HTML editor or visual editor.

All the other pages and posts on the site display correctly.

Doing a MySQL ‘CHECK TABLE’ on the various tables reveals no problems, but if I look at wp_posts, the record with the revelant ID does have a post status of ‘publish’ and contains no text… yet as I say it displays correctly.

There are records, with the post status of inherit, which do have the text that displays: the page has been edited successfully several times in the past. However if I compare revisions, WP reckons they are all identical, i.e. empty.

I am wondering if there is some database corruption involving the bit of WP that displays pages thinking the relevant ID is – say – 15, but that the rest of WP reckons it is – say – 16.

Suggestions welcome. At the moment, I am being tempted to copy the correct text into record that the editor thinks is the page, but if there is some corruption, I don’t want to make things worse.

Is there something that checks the content of the database for internal consistency?