No Favicon On Safari with assets/favicon.ico

When setting up for a project I had running locally, I noticed the favicon wasn’t displaying what I had set. I have the assets/favicon.ico set up relative to and I can see the html header is correct when inspecting the element on the page:

<link rel="icon" type="image/x-icon" href="/assets/favicon.ico?m=1618345048.8448246">

When I checked with Chrome, the favicon displays fine.
I tried restarting Safari and reopening the page (localhost) but there is no change.

This isn’t an app in production, just a personal project, but I’m just not sure why Safari is fetching the standard plotly logo vs. the favicon.ico I have in place.

Does anyone know the cause of this behavior? I couldn’t find much helpful information on this from the Apple/Safari side of things. Is anyone else experiencing this or something similar?

I’m using Safari Version 14.0.3 (16610.

I updated my machine and the favicon is now working as expected.