Map alignment off when zooming out

Confirmed on Windows 10 using 1.4.2.0.

I have uploaded the following demo world file to my OneDrive account because it's too large to attach. Anybody should be able to download it. It was last opened under 1.0.9, and saved on 23 May 2017.
MCPE-27025.mcworld

Steps to reproduce:

1. Import and open the demo world.

2. Teleport to -2297 71 -1246.

3. Open the chest beside you and take one of the maps from slot 0.
   Note: The upgrade path has named all maps "Map 0", a bug that has not been reported to my knowledge.

4. Inspect the map. Note that it's a level 2 map that contains your player marker.

5. Zoom the map to level 3. Inspect the resulting map.

Expected results:
The level 3 map covers the area surrounding you, is partly filled in, and displays your player marker somewhere inside it.

Actual results:
The level 3 map is blank and your player marker is off the northwest corner. If you teleport to 0 90 0, you'll see that the level 3 map is centered there, almost 3000 blocks away. If you zoom the level 3 map, the level 4 map is also centered at 0 0. Clearly, these maps will not align with correctly centered adjacent maps at the same level.

The cause is that the map entries in the level database all have xCenter = 0, zCenter = 0 for level 1-4 maps that haven't been created by zooming yet, and zooming does not calculate where the center should be. I don't know whether that was itself caused by an upgrade path error or by a bug in the zooming logic, but I assume one or the other should have recalculated the center point.

Note that the various reporters of this bug and its duplicates focus on the alignment issue and don't mention that the zoomed maps are all centered on 0 0. I believe I'm describing the same bug, but that the others are probably mapping close enough to the world spawn point that it's reasonable for a zoomed map to cover the area near 0 0, so they didn't notice. If anyone has a pair of zoomed maps that can't be aligned, and neither of them is centered at 0 0, there may still be more to this bug that hasn't been revealed yet.

To the developers:
I have uploaded a second world file to my OneDrive account: MCPE-27025-2. It was last opened under 1.4.2.0 and saved 21 June 2018. 

In this world, the local player is holding two maps in slots 0 and 1 of his hotbar. Both maps are centered at -2304, -1152. Map 28 (in slot 0) is an older map created in an unknown release. Map 83 (in slot 1) was created today. With an NBT editor, I looked at the precalculated center coordinates for these maps at all zoom levels:

It seems clear from this data that the old Map 28 center coordinates for levels 1 to 4 were incorrect, and that those for the newer Map 83 are correct. This suggests that there was a bug in a previous release that was fixed in a later release, but that the upgrade path either did not recalculate the centers for zoomed maps that had not already been activated, or recalculated them incorrectly. This would be causing zoomed copies of old maps to be misaligned.

To those watching this issue:
It isn't obvious, but the game calculates the center coordinates for all zoom levels at the time you activate the level 0 map and saves them in the world file. In some past release(s), this was being done incorrectly, so when you zoomed a level 0 map the zoomed map wasn't properly aligned to the grid, but since all zoomed maps were being offset in the same way, their misalignments canceled out and there didn't appear to be a problem. The error was corrected, probably in 1.2.11, at which point any new level 0 maps you activated would generate properly aligned zoomed maps, but earlier maps that had already been zoomed remained misaligned. So in other words, it's not the new zoomed maps that are misaligned, it's the old ones; you just couldn't tell because they're all offset by the same amount.

We'll have to wait and see whether the developers can re-center the old maps, but I'm afraid that even if they can you'll still have to fully re-explore them to redraw their pixels, and it will be a lot harder to do that for an already filled-in map than for a blank one. So the bad news is that it's probably going to be easiest to just trash all your old (pre-1.2.11) level 1–4 maps and recreate them. You can keep your old level 0 maps, but you can't zoom them, so you'll also have to create some duplicate level 0 maps to zoom from.

Of course, you can just keep your old map walls, too; you just can't add to them. But if a wall map already covers all the areas you care about, there's no need to recreate it.

Thank you for your report!
However, this issue has been closed as Won't Fix.

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