I've discovered why promotions and sales aren't showing on the top of the listings anymore on computers and why they aren't showing properly on mobile.
When you have a promotion that ends, don't click the drop-down and copy it to create another promotion or sale. Use the drop-down at the top of the promotion page and create a new one.
When I just copy an ended promotion, it doesn't show at all on the app and mobile site. It shows on desktop but the red highlight doesn't show at the top above the photo. It only shows down below the description.
So when a promotion or sale/markdown ends, don't just copy it. Create a new one and it will show the way it should on the app, mobile site and on computer.
I was getting mad because I thought eBay was purposely not showing my sales on the app and mobile site. Turns out it's a glitch when you copy an ended promotion. Sometimes when you calm down and try to think about reasons why things aren't working the way they should, the answers come to you and it isn't what you think it is. It's time we all stop thinking eBay is conspiring against us and start working out the sollutions to these promblems without freaking out.
You're welcome!
Good Luck and Happy Selling!
