I was having the same issue, I contacted the live SS chat and this was their response:
Thanks for your patience here while I had a look. I can confirm this is due to an issue on our end. Our engineers are aware of connectivity issues impacting some Squarespace sites and we hope to have a fix in place soon. Apologies for any inconvenience caused, and thank you for your patience.
They also confirmed the site/template should be back to normal when their issue is fixed, and they are working to get it fixed asap