Platform: Pc
Description: My very first reaper gave absolutly ZERO loot. After this all tanks i killed also gave zero loot, both me and my duo experianced this
Images / Videos: https://youtu.be/zY6yuTHTdd0
Host or Client: host
Players in your game: one
Specifications: gtx 1660, ryzen 5 2600, 32g ram
This has nothing to do with the Reaper.
Yesterday, after playing for some hours only with 1 character, to get more room in the Plundra, i decided to check my other 3 characters inventories.
So i switched between them some times, putting items in and out.
After that i went back with my primary character.
After a few minutes destroyed a Military Tank and it had Zero loot.
I tried some other machines and it was the same, no loot.
Restarted the game and it fixed the issue.
PS4
Solo version
Steps to reproduce ABOVE
doesnt explain why my duo got zero loot. its BS. took me 120ish hours to get to the point to take it down and what did i get? NOTHING
Well I have nothing to do with it!
I just gave you a temporary solution, restarting the game should fix it until it happen again.
Some nights you just gotta cry yourself to sleep
It took me 2-3 hours to get a Reaper spawned, and 20 minutes to defeat it. Don’t try to tell us you’ve wasted 120 hours! 
Definitely not intended, either way. I’ll make sure to poke somebody about this issue.
so you joined a new game and within 2-3 hours spawned a reaper? wonder how you did that
What NJR87 means, is that it takes 2 in-game hours before another rival (regular or Reaper) can spawn in since the last time rival spawned in.
i know i was joking lol. took me 120 hours becuase i was doing the first few missions when i learned about it and wanted to work towards it
Yeah, what @Aesyle said.
To be precise, the first time I played after the Reaper was introduced I went to Himfjäll, that already had a region score of 20, and I began grinding machines. Needed to take out a couple other rivals along the way, to make room for a Reaper. 2-3 hours was actually a very specific example, so for that I apologize. 
Raising a region score from 0 to 21 (or more) takes a bit more time than that. After that, it’s also a game of chance if the game decides to spawn a regular rival, or the Reaper.