Editor Links disappear on publish

Hi There

I notice if my client adds an external link via the Editor on a button, when they click ‘Publish’ the link disappears. Any reason why that should be happening?

If i add it in my designer view and click publish it doesn’t

Here is my public share link: https://preview.webflow.com/preview/securities-trading-technology?preview=4e542dac7d8a6477ae3abd3526157dac