In 1.16 I explored my world in an area of ​​4k by 4k blocks to prepare it to jump to 1.18, when I updated it to 1.18 (I skipped 1.17 because this version corrupts already generated chunks of my world and any other world that I create in that version MCPE-153609), I found these chunks in the form of lines from different biomes crossing the biomes already generated, I had to go back to a backup of the world and walk through the entire Mooshroom Island biome to save it because a line of chunks from another biome had ruined it. (See BugR1.png and BugR2.png)

I attach my map that since 1.16 I had already explored it 100% (See BugR3.png and BugR4.png)

STEPS I did, to supposedly generate the world without wasting time:

(Minecraft 1.16.X)

1. Rendering to 52 chunks (maximum allowed by my Windows PC)
2. Elytras to explore the map
   Repeat the step with the next 36 maps (I haven't even been able to finish. See BugR4.png)
3. Update to 1.18.X (The most current is 1.18.12 so far)
4. See how Minecraft didn't care that I rendered 52 chunks around and makes lines of chunks with other biomes in places where I literally PASS SIDE of them (See BugR1.png again), you have to OBLIGATORY walk over the chunks that are about 4 chunks away from you (It's what I did in BugR2.png with the mushroom island) , if not, Minecraft "Regenerates" them.

(Context of BugR5.png): I am on the left edge of my map, this map is one of the edges of the set of maps that I have explored, and it is clear to see where I have stopped exploring, even though the rendering generated even more chunks forward, but I didn't go through them and Minecraft didn't care that I had already generated them with the rendering at 52 chunks.......

It is quite annoying that this happens, and I hope that someone else has reported this.

Thanks for attention. And I hope they don't cancel this ticket and all this explanation for something meaningless or of little relevance. It's not the first time I've seen in other tickets that moderators have this kind of behavior.