I recently noticed that somehow, a smart playlist of mine which contains 700+ titles doesn't show all of them on my iPhone 7. I tried to delete it on both my mac and my iPhone, but it doesn't seem to solve the issue. I've also realized that all the titles excluded from the smart playlist on the phone before and after deleting (and recreating) it hasn't changed.
How can I solve this problem? I'm currently using macOS High Sierra (10.13.6) and my iPhone is up to date (iOS 12.1).