Illfonic only knows how to wave spawn OP though they handle pig spawns like this intentionally.
Ok so pig theory 101.
To keep pigs near FT and create counterplay - Pigs are spawned per player in the vicinity of the player after a certain amount of time. You’ll never see pigs just roaming around away from the FT. You’ll also see if the FT gets stalled at an area for awhile, you get like 5 pigs in one spot - these are the wave pig spawns. If the FT runs around a lot it’ll despawn pigs quite often which encourages the FT to keep moving.
You didn’t get any pig spawns because when the FT stands way out in the water near the boundary in Backwater there are no pig spawns there so the game just doesn’t spawn pigs until they return to a mission area, road etc that has a pig spawn nearby.
Standing way out in the water throwing medkits is an FT strat that just makes that map worse but the best way to remedy this is to just caster them from the mainland with the cover of trees because while you’re doing that they’ll A. Get a little closer to you and eventually head back near the shacks while you minimize damage to yourself (dont jump out into the middle of them in the water, it’s the worst possible scenario for pred in this game. Time is on your side if FT isnt doing the mission)
And B. The game will eventually spawn the pred its mainland pig (near that tree in the direction of the exfil usually) because the pred gets the 5th pig in vicinity of the FT.
Pred pig theory is harder to test because pred pig seems to spawn way slower than the pigs that spawn on the FT (and despawns after like one good leap) but option A will net you a pig everytime if you’re patient and you don’t let the FT bait you into the water.
Tl;dr and final note of pig theory: When in doubt, poke and let FT return to mission area away from the map boundary.