This issue was brought up in the snapshots, and was "fixed", but is currently an ongoing issue in the current 1.11 release so I thought I'd bring it to light again. On top of that, this ticket doesn't just discuss the frequency bug, but also the fact that they are spawning within the first five days and within villages.

Client was updated properly, and the world I'm experiencing the issue in was created after the update to avoid transitional issues.

Within the first 5 minutes of playing I was attacked by an Illager patrol. In the bedrock edition these are not supposed to spawn within the first 5 days of a new world. On top of that, the spawn was in the middle of a village, which also isn't supposed to happen. This results in an immediate raid upon killing the leader. After that, I experienced about 3-4 illager patrols per minecraft day, several of which I witnessed appear in the middle of a village. To me, this is just absurd. I was hoping these would be a rare occurrence, not something that happens faster than crops grow. At this point I have a small stockpile of the Illager banners.