I've had an Nvidia shield for about 2 years & its a fantastic box. I've been using APK movie and TV apps such as cyberflix and catmouse, however I have found that these APK's have stopped showing 1080p links. Anybody got an idea why? And what fixes would you recommend. Cheers!
You're pretty much at the mercy of whatever free sources are available in 1080p on the internet. Apps like Cyberflix and Catmouse merely act as glorified search engines that find and curate those sources in a Netflix-like manner for viewing. They aren't repositories for content and can't deliver additional links in of themselves.
That said, you might want to consider subscribing to a debrid service like Realdebrid. For a minimal cost, a debrid service can increase your access to high quality 1080p sources with less chance of buffering as well. Both apps that you have mentioned above utilize Realdebrid.