@Anat13 That worked, thank you! I had to keep my current line of code and add yours to remove both underlines:
//remove underlines from hyperlinks//
.sqs-block-html a {background-image:none!important}
/* Remove non-background image underline for heading and paragraph links */
h1 a, h2 a, h3 a, h4 a, p a {text-decoration: none!important}
I chatted with Squarespace and they said they weren't aware of any issues or recent changes that would cause the problem and they said I shouldn't use CSS on my site 😒
I'm still wondering what is causing a double underline on my site, but at least I'm able to get rid of it now.
Thank you SO much!!