Hello,
1/ Do you have this problem when the parent theme is activated? Check if the issue is caused by custom changes in your child theme.
2/ Try to disable all the third-party plugins (including cache plugins), that do not come bundled with XStore https://www.8theme.com/documentation/xstore/plugins/included-plugins/ , clear cache of browser, and check then. Maybe one of the additional plugins is a reason for the problem.
Regards