Please make sure that you have added an image gallery for each variation by editing the product. Then clear cache and check back.
If the problem continues then deactivate all the third party plugins and provide with the admin panel login details of the website then we will troubleshoot with the theme plugins.
Hello, thank you for your respond. I have checked all of your tips. I will provide you admin access to check. I have also created a copy of the variation product where you can play around with.
Please deactivate all the third party plugins activate the parent theme then clear cache and check back.
If the problem still continues then leave all the third party plugins deactivated and tell me with the permissions to debug then we will troubleshoot with the theme plugins.