New wordpress release breaks quantity increase

Hi,

I updated my site to Wordpress 5.6 last night and afterwards I was unable to increase the quantity of items I wanted to purchase from my store.

I troubleshooted for a few hours and found that is was the theme that was not working with Wordpress.

After testing many things I found if I changed the theme to something different the quantity buttons worked.

Things I tried
1) Removed all custom CSS - in case it was effecting it
2) Removed all plugins apart from woo commerce and other plugins needed for the store to actually work - again this didn't fix the issue.

I had to roll back to wordpress 5.3.3 to get my site working again.