Ben Wheatley and Bong Joon-ho were undoubtedly making their respective 2017 releases, Free Fire and Okja, at approximately the same time.
So only a certain random felicitnousness could have led them both to use John Denver's "Annie's Song" in virtually the same context in their movies.
If you don't know the song -- and I didn't before I saw Free Fire -- it's the one that goes:
You fill up my senses
Like a night in a forest
Like the mountains in springtime
etc. etc. etc.
In both movies, this soaringly sentimental ballad is used as an ironic counterpoint to something going on on screen, and kind of a similar thing in both cases.
In Free Fire, it's playing on the 8-track player of a van that's making its way through the impromptu war zone that's popped up in a warehouse where an arms deal went south. If memory serves, the driver may have been shot, leaving the vehicle to roll to a stop of its own accord while the music blares.
In Okja, it plays directly over a scene of chaos, as police try to subdue animal rights activists in an underground convenience store after a super pig has plunged through it, knocking cosmetics and cold medications hither and yon. They shoot tranquilizer darts at the activists and the super pig, and the activists elegantly defend themselves by deploying umbrellas in the direction of the blasts -- which, indeed, are quite effective in stopping this particular form of attack.
The only fundamental difference in the way the song is used in the two movies is that the moment in Free Fire is quiet, by that movie's standards, as the Denver song is the only absurd interruption to a scene where everyone is on tenterhooks to see who will expose himself next or fire the next shot. In Okja, it directly scores an action sequence, similarly absurd for the combatants and some of the details of the scene, and similarly operating as a counterpoint to what's going on on screen. The action being in slow motion and devoid of its diegetic sounds means that it's also sort of "quiet" in the same way that it is in Free Fire.
Now, if a third 2017 movie also uses this song in even a remotely similar context, that will be really weird.
And if a 2018 or beyond movie uses it, that will be a ripoff.