Thanks Dave. Would you mind try this?
Pulled the small portion of the clip onto your timeline, then turn your gnarbox box off and try to lengthen the clip on your timeline.
My thoughts are that if it lets you, it might still be importing then whole clip onto your iPad somewhere even if it isn’t in the LF user media, gnarbox folder... which might explain why it’s using up storage space.
Downloaded clip DJI_0643.mp4
Using cable and mass storage mode copied clip to Gnarbox\LumaTouch\Sam
Connected phone to Gnarbox using WiFi
Navigated to directory with LF
Clip showed with 'Processing...' underneath
Clip shows DJI_0643.mp4 22:18 3840x2160
Tapped clip to select
Clip shows in preview window 0:00 [22:18]
(Checked LF directory using Files app - nothing downloaded)
Using sliders below preview window selected part of clip 13:08 [3:12]
Showed Downloading Media 'My project (25fps) 3.10 duration
Clip info on timeline 3:10 DJI_0643.mp4
Checked again with Files app
Now showsLumaFusion\LibraryMedia\Gnarbox\DJI_0643-669 000-3240 10:49 68.2MB
(Original file size 282.5 MB)
So in my case it has worked correctly and only pulled in the trimmed clip??!!??