Hi
You cannot "prevent URLs" from changing, but you can ensure they are really clos to what they were. In many cases, they will be nearly identical.
For example when we switch on optimisation, the url changes to include the category like below
https://www.xxxx.com/policies/privacy-policy which was originally https://www.xxxx.com/privacy-policy
Which is exactly what it's supposed to do. Instead of using the menu item as Joomla does, we only build URLs based on the content itself. In your case, the category "Privacy policy" is a sub-category of the "Policies" category, so the URL is policies/privacy-policy, when you use default settings.
You can change the URL structure by going to the
Extensions ->
Joomla tab of sh404SEF configuration, and change how "Categories" are included in the URLs. You will need to "Purge" URLs, with the Purge button, so that new ones are created again.
in some cases a /table is added to the url.
This is also controlled in the same section, and is a
good thing. Joomla has 2 types of category views: blog and list. Back to your category "privacy policies", with default settings, a link to the category
blog view will be /policies/privacy-policy, while a link to the
list view will be /policies/table/privacy-policy. You can change that behavior with settings just below the category ones. Again you'll need to purge URLs so that new ones are created again.
Rgds