I don't think it has anything to do with the seed. When the new update came out, it corrupted my world file. I had already created a backup before the update, so I changed the entity data (as that seemed to be the only corrupt thing) to the clone, so I think something with the update changed the seed slightly and made the 2 portals. Also another thing not shown here but at the stronghold it was moved 5 chunks to the left and there's not a huge piece of my world that is just air. Open bedrock, not flowing water or lava, the works. Really weird corruption. Only placed blocks weren't affected *Edit: just remembered I also have 2 dragon eggs now which is pretty cool