- you've turned off automatic translation but content is still translated automatically.
- this is causing the overwrite of your manual changes.
- specially some words which are not correct as per automatic translation, so you made manual changes to correct these but still are overwritten when content is changed and translation is automatically updated/overwritten.
Reference to our recent chat, I need to take a closer look at your site. I request temporary access (WP-Admin and FTP), preferably to a test site where the problem has been replicated. So the live site isn't compromised.
Your next answer will be private, to share this information safely.
Also provide detailed steps to reproduce the issue and links to pages in the admin and on the frontend.
IMPORTANT: Please take a complete backup of the site to avoid data loss. I may need to activate/deactivate plugins also.