It seems to be some broken HTML structure on your product page and causes this https://gyazo.com/f0c6822ff7c2d784dde3b398994d9d04
It may be somewhere in your text fields like product short or full description. Please, check all these areas. You can check footer widgets as well.
ok One thing i notice is that when i do so settings/customization on the child theme and activate the main theme and go back to child theme.. all the settings i did are gone. Like the header, colors settings etc. why is that and how to avoid this? Now i have to do everything back from start.
Such behavior of the child theme is not correct. Seems your child theme is not correct, try to take from the theme folder the child theme and reinstall, if the problem remains, provide the site admin access to the private area, make the full back up of the site.