This is due to technical reasons. Trimming is possible only at fixed 1 second intervals within a clip.
- Why does Storyteller on my Lumia tablet pair automatically with my phone's Lumia Share app?
- Does the Lumia Share app work on all Lumia phones?
- Does the Lumia Share app work in all Wi-Fi network environments?
- Is there a way to share only some images with the Lumia Share app on my phone?
- What is Lumia Share app?