Sheltered Hollow : The Scavenger droid will not spawn, therefore no treasure.

@misterfx3  Try coming back later, fast-traveling somewhere else and back.  You'll need to progress a bit in the story, but that shouldn't take long.

As a side note, when I missed a scavenger droid, usually because it dug for cover before I could get to it, I found I needed to quit to the Main Menu and reload into the save to have it reappear, or else wait longer than I wanted to.  So save at the meditation point before looking for it again, which you'll do by default if you fast-travel there, and just reload if you don't catch it on the first try.