Hi,
I seem to recall the template for the action email for abandoned cart included a link that would return the user to their cart in one click. That link seems to have disappeared from my email template.
I’ve replaced it with our web link, but the cart would only still be present if the user opens the link on their same device.
Is it a figment of my imagination, or should there be a way to return the user to their cart automatically? If yes, what is that link?
Mine is still present, you’re definitely not crazy!
Maybe try running an Action Email Setup to reset to default?
Alternatively, here is the link from our email. Looks generic enough to paste into your email to test. Change YOURDOMAIN to your website…
https://YOURDOMAIN.com/index.cfm?method=cart.oneClickDuplicate&orderID=//OrderID//Using the link that @rmcguire posted and replacing with your website URL will work. 
Just make sure that you only use it in action emails as the //OrderID// tag will not generate in other email types.