While watching videos inside of Safari on any iOS device, the video will automatically navigate to the end after pausing and locking the screen for some time.
This has been happening as of iOS 12.2 and doesn't seem to be specific to any device. As long as you load up a video in Safari, watch to any amount of time, then pause and lock the screen. Wait for 10-15 minutes. The video will have navigated to the end as if I had watched it all the way through.
This doesn't appear to be an issue with the video playing in the background because the lock screen controls will show no progress and no audio will play while the phone has been placed in the lock state.
I have replicated the issue on:
- iPhone X (iOS 12.2)
- iPad Pro 10.5" (2nd Generation, iOS 12.2)