NOTE: This issue no longer happens to me as of 1.16.201 hotfix!! I have two sets of rails just like the description in my world. They have not been removed!

Bug Description:

When I Place Rails Downhill in Survival And Leave The Game, Upon Rejoining They Are Gone. The Rail Item Doesn't Drop. It Just Disappears. This is a HUGE Waste of Resources and is Very Annoying. (Singleplayer World [Only Been Used in Split Screen]) I Have Not Been Able to Recreate This Bug in Any Other World, So Maybe It Has to Do With My World Specifically?

Expected Results:

• Rails Stay in My World Until Manually Destroyed or Griefed by a Mob/Block
• Minecart Stays on The Rails

Steps to Reproduce:

I'm Not Entirely Sure, Maybe it Has to do With Chunk Borders, But Here's What I Do to Reproduce:

1. Open Minecraft on Nintendo Switch
2. Set Your Render Distance to 14 Chunks
3. Create New World & Use Seed "29232013"
4. Go to Around Coordinates Shown in Screenshots
5. Place Rails Downhill as Shown in Image
6. Play World For a Bit More (Minimum 5 Minutes)
7. Exit World With These Chunks Loaded in
8. Wait a Bit, Maybe Play in a Different World
9. Close The Application
10. Rejoin World
11. Check Coordinates of Rails

Please Let Me Know in The Comments of This Report if You Reproduced Successfully, and if You Got The Results I Did (Below).

Results:

• Rails Disappear (No Item is Dropped)
• Minecart With Chest Gets Pushed to Sides (But a Few Blocks Down From Where it Was) of Where Rails Should Be

Things to Note:

• Minecart With Chest Gets Pushed to Sides (But a Few Blocks Down From Where it Was) of Where Rails Should Be
• I Marked it as "1.16.201 Hotfix" Even Though it Was 1.16.100, 1.16.101, 1.16.200, and 1.16.201 (It Wouldn't Let Me Select Those)
• Below I Have Images of Me Replicating The Two Times it Happened. I DID NOT get a Screenshot of it When it Happened, but I did Replicate what it Looked Like. That's What You See in The Screenshots.

• I Do Not Have Realms, I Can't Upload The World.
• My World's Seed: 29232013
• I am in Survival Mode

Questions I Have:

1. Is this a duplicate of an existing issue, or is this a new issue?
2. Should I make a copy of my world and try the bug in creative mode?

Updates:

• (Saturday, March 6, 2021) I Played The World Cross-Platform With My Friend, Who Was on X-Box.
• Important: I Tested it in a Different Part of My World Which is About 20-50 blocks from where the bug happened. Results were good. I did not have any disappearing rails. (This Leads Me Further to Believe it Has to do With Chunk Borders)
• Also Note Above That I Had Made a Much Smaller Rail-line, Unlike The One in The Images Below

In Response to [Mod] GoldenHelmet:

Question: How do you "leave the game"? If you are going straight from the world to the Switch home screen and closing the game from there, then you are not giving the game a chance to save your most recent changes. Does the issue still occur if you use the "Save & Quit" button and wait for Minecraft to return to the list of worlds before going to the Switch home screen?

Answer: Yes, Even When I Use "Save & Quit". I never leave this world by closing the game besides when it freezes/crashes. I will play for minutes to hours after I place down the rails. I have only done it twice, them disappearing both times, and I won't do it again until this issue is fixed, except for if you guys need some more pictures to see if it disappears. As far as I am aware, I have been signed in to my Microsoft Account both times.

In Response to Others:

Nothing Here Yet