Clear Browser cache
- Refresh the page with the key combination: Ctrl+F5
- Erase the browser cache
Unfortunately, next-gen projects still have some bugs and it is hard to reduce to the root cause in some cases.
One of the bugs is: Time tracking is not present in the next gen issue layouts, but you can still able to log work on them, but not report.
To fix this, please add Time Tracking field for all of your issue screen/layout and next-gen issue type.