Page Load animation skips the animation and instantly changes

Hey there!

I have a page load animation to grow my hero background from 1280 px to 100% width over a duration of 1s. For some reason, though, the animation happens instantly. It’s worth noting that there’s also a normal “loading” animation combined in the same interaction.

Any ideas how I can get this to animate after the normal page load? It’s kind of jarring to have it grow instantly.

Here is my public share link: LINK
(how to access public share link)