Hello,
Thanks for your Continued Patience!
We have checked this out and can confirm this behavior. We Apologies about the Inconveniences related to this, however, this appears to be something related to the Isotope Plugin which initializes the Grid on Window Load. We are looking into why this is occurring and trying to work on fixing this.
Meanwhile, simply removing the .grid-container Class from the Shop Wrapper should fix this issue automatically. Additionally, this should also fix the Overlapping on Mobile Devices.
Hope this Helps! Rest assured, we are looking into this.
Let us know if we can help you with anything else or if you find any further issues.