If anyone is wondering, I tried rolling back the website frontend (on a test server) to see if it would solve the issue with "Show context". It didn't solve the issue, it seems to be a change on the server side that's conflicting with the front end, as apps don't seem to be affected.
I recognise not everyone is technical so I'll try to explain some key concepts.
The website that you access and the server that works out what content to show are two separate things. When you access the website, it sends requests to the server for what content to show.
When you use an app, the app sends requests directly to the server similar to how the website does. Therefore issues on the website don't necessarily show up in apps, because the app doesn't go through the website.
I'm happy to explain other parts if anyone wants me to.