Zend certified PHP/Magento developer

Magento 2 Catalog URL Suffix not working

The website have 12 store views.
6 of them have .html suffix for products while the other 6 doesnt. I am not sure how that happened.
I edit the store settings for all of them to have the .html suffix but it is not working even with the magento flush cache and index reindexing.
Same issue also happens for the product category links.

I tried to follow the deleting of var/view_preprocessed/pub/static/adminhtml and redeploying but the issue is still there.

May I know what fix or steps may I do for this? Also, is it safe to delete all the /var folder? I have a system backup but im unsure if the /var folder will be restored if ever something happens.