Recently when playing on a realm with a couple friends, I was placing blocks when one time I placed a block on top of some grass and it just disappeared. I would place the block, it would appear for less than a tick and then disappear. I tired mining the blocks that I was placing the blocks on too, and they just immediately popped back into place, and I wouldn't pick them up. (It's also worth noting that I had Advanced Tooltips on, and they didn't take away durability from my tools when I mined them). I turned Chunk Borders on, and as I suspected, the glitchy blocks were all within a couple chunks of each other. (I didn't count, but I suspected around 6 glitchy chunks with this problem.) If I placed a block one block out of a glitchy chunk, it would be fine, but one block in, and it would disappear. I can move blocks in with, pistons, but then they're essentially stuck there. If I place water down it just disappears as well, and the bucket empties. I tried getting my friends to mine the blocks, but they had the exact same problem. I can still walk around in the chunks with no issues. I tried getting all my friends and myself to leave the world, and then relog, but it didn't work. Normally I would be fine with a problem like this, but the glitchy chunks are exactly where I want to build my house, which is very annoying.