I’VE WORKED IT OUT!
Okay so, after experimenting on a separate computer, I have come to the conclusion that the main reason it spawns hordes for some users and not for others is because of this one simple factor: Lag.
The slower computers seemingly generate large amounts of enemies on Day 3, whereas on this faster computer, I have only managed to get a group of 2 goblins on Day 5, which would make me assume that a slower computer will run ticks at a faster rate than a faster computer.
Therefore, a slower computer will probably tick maybe 5x faster than a faster computer, due to the fact that it covers more time in the systems mind, where in fact less time has been covered.
So, the way this would need to be fixed is that it would have to check based on game time, instead of by tick intervals. Because a tick will run at the same speed regardless of the computer, but game time will run slower or faster.
Hopefully this helps with the random horde problem! Maybe this is why the dev team has not discovered the problem before the release!
EDIT: We are going to test this theory, post your computer specs, the day you encountered goblins and the quantity below! Thank you