Size chart page will appear on mobile but no on desktop

[Packo]

In the red shirt when you click on the blue link to show size chart the chart don't appear on desktop but on a mobile will. Any ideas why? 

Followed this tutorial: https://shopify.dev/tutorials/customize-theme-add-size-chart

But instead of putting the link above the buy button, which in that case works perfectly, I put it to description.

Page: https://90v0k5b6f8sqp4h6-46295777437.shopifypreview.com