so in my single player survival world the spawn chunks and spawn area happen to be an island, a fairly nice size for a few players but small and limited resources above ground, there is a vast mineshaft right below my house and a extensive line of normal caving from the surface with a Skeleton Spawner located farily well down one of the cave lines, despite the nice generation below there is no Villages within 1000 blocks, as i made a copy, with cheats on and located the closest two.

 
The Issue is that despite there being no village within 1000 blocks at least i have been getting illiger patrols quite consistantly, all been around my storage place ive been having my attention on with building, currently ive defeated four patrols with never setting foot within 200 blocks of a village

Attachments show some pictures of the environment i have set my base up around, as well as the size of the island and the locations of all the builds, Illigers have been spawning around and within my warehouse / the building without a roof that has scafolding blocks all around it

pictures are - proof of illiger defeats - front of starter house - Airial look of island towards house - Airial look of island towards tree farm spot, and cave stone mine entrance (No Particular Order)

Yes, apologies, i do ramble on a tad dont i......