From what we've been able to determine so far I think this is possible, if not probable. In my mind, the most likely scenario is that these were created by INRA. They are scanning for a specific type of ship. Thargoid ships. Perhaps they have determined that Thargoids are making a resurgence and have created the UAs to look for them and disable them via the Mycoid virus. It makes sense once you consider the use of Morse.
So the reason that we cannot find anything now, would be that we have to visit a planet to discover it. Seems plausible. It's a shame there's no hint of something unusual there in 1.4 (so far).
I just had another thought. 1.4 also introduces salvageable wrecks. I wonder if one of these might be of non-human origin and dropping a UA in there might provoke a different response from the UA after it scans the wreck.
That's an interesting idea. So it might determine the original ship type from the wreckage.
I tried transcribing some Morse data from a dropped UA recording, but the small excerpt I collected wasn't enough to generate a decent image in the HTML sketcher, though some of the triangles were symmetric enough to suggest it might become a ship given more data.
We'd need to do enough drops to collect a repeating sequence, and string them together. That should work as long as each drop yields a different section of the sketch, otherwise the lifetime of the UA will limit the detail of the drawing. How many triangles does it take to draw a Thargoid?
Might I suggest that the first step would be to try and see if we can extract the Morse from a dropped UA for a simple ship (like
Rizal's sidewinder, which turns out to be only 7 "words") just to verify that the dropped UA works as expected compared to a free-floater.
Then if that works out, head off to find a wreckage.
Even then we should still use a simple ship like a Sidewinder to run the wreckage test, as we can quickly detect if it's just drawing the Sidewinder again and don't need to gather many drops worth of data to get a sketch back to find out.