Can create draft, cannot update afterward

I recently migrated and upgraded a clients WordPress install.

The problem: Can create a draft of a post, but afterward nothing in the “post.php” page will update the database entry.

Notes:

If I change from Draft to Pending or Published from edit.php it will update the database entry, but that is the post_meta, not posts, table.

When hitting Update in post.php I am taken to the base URL (like I was in https://example.com/wp-admin/post.php… and I Update and I get taken to https://example.com/ with no update occurring).

I have tested removing the theme and disabling all plug-ins. (I read all of the posts about themes and plugins causing problems)

My gut feeling is there is an encoding mismatch between the wordpress install and the database tables, possibly an indexing issue, but I don’t know why that would cause what is happening here. I did try optimizing and repairing through phpMyAdmin.

To recap:

I go to wp-admin, create a draft, click Update. I am taken to the base URL. The draft appears in the database. After that I am unable to make any changes to the entry in the database from post.php.

Does anyone happen to have any advice on how I might fix this?

Thanks for any help you may be able to provide,
Jay