added a “New Colour Source” (colour:black , duration:68) to an existing clip in a Sequences reel.
(Splice selected). It’s possible to move them inbetween the different shots but I am unable to place it at the end of the clip without gap.
Can you not do it in the timeline? Just go to the end of the timeline, grab the color source clip and drop it into the timeline after the last frame. It should “just work”.
I don’t use reels ,I drag and drop the colour source just at the end of timeline.
With snap function this is very quick. Or with append shortcut. If you open the edit as record timeline
select the colour source and press the shortcut you’re done