Matt J. I'm not sure if you're aware or if this is the right place but I also noticed the placeholder logo shows up on "dark mode" but my logo will show up on light mode only, like it is ignoring my logo on dark mode. I'm working with a logo with a dark outline but it is also happening with a gray logo I tried.
Some of my clients work from their phones and will be pulling up the link on their phone first. I'll tell them to view on desktop first, but it will be great once mobile is ready!