Mountain Zone Grid Bug / Desync & Shrinking Tiles after Land Expansion

Update & Root Cause: The Half-Tile Grid Shift

I did some final, precise checks on how the railway tracks behave before and after connecting to the external boundary, and I found the exact visual and technical trigger for this bug:

• Without the track connection: The internal mountain tracks run smoothly right up to the edge of the unlocked mountain area. Up to this point, all mountain objects can be placed seamlessly without any issues.
• After confirming the track connection: As soon as the external connection is confirmed and active, the internal mountain tracks physically shift forward by half a tile into the still-locked/unexpanded mountain area.
• Why the gap/desync happens: Because the game forces this half-tile shift due to the connection arc sitting in the mountain zone, everything downstream gets misaligned. However, building objects can only snap to full, whole tiles. This mismatch creates the shrinking space and the "overlap" error right after the track connection.

I have captured 3 screenshots documenting this:

1. Preview: The external track connection is only planned (green connection points shown but not confirmed), and the tracks end properly at the unlocked boundary.
2. Confirmed: The track connection is built, and the internal tracks visibly shift forward by half a tile into the unexpanded area.
3. Placement: Mountain objects line up perfectly up to the track connection, but are completely ofset by half a tile after it, causing the placement block.
4. 

    

Call for Testing: Can anyone else confirm this Mountain Grid Bug?

Hi everyone, I would love to know if other players are experiencing this exact same issue. It would be great if some of you could test this safely in your own cities to get some confirmation.

If you'd like to help, here is the scenario to look for:

Do you have an external railway track connection going out through the Mountain zone, AND is there a Mountain building placed exactly at that connection point (like in Frosty Fjords)?

How to test it safely:

1.  Go to that specific area where your mountain buildings are placed tightly together.
2. Crucial detail: Choose a building (whether it's a standard Mountain building or a Mayor's Pass item) that is tightly surrounded by other mountain buildings on BOTH sides.
3.  Simply lift this middle building (please do NOT store it in your inventory or move it away!).
4. Look at the bottom of your screen. Do you get a message saying the building overlaps with another object, leaving the green checkmark greyed out?

(Important: If you see this overlap message, just tap the blue 'X' at the bottom or the red 'X' directly on the building to cancel the action. The building will safely snap back into its place without ruining your layout).

Why this matters: If you ever want or need to remove or replace such a mountain object sooner or later, this bug kicks in. Not only can that specific building no longer be placed back, but the available space itself has shrunk, making it impossible to fit another object of that size back into that slot.

I would really appreciate it if anyone with this specific setup could test it and let me know if they get the same grid error. The more confirmations we have, the better! Thanks!

Update on this issue:

I’ve done some more testing and figured out the exact trigger for this mountain grid calculation error. It is 100% reproducible and directly caused by the external railway track connections.

Here is what I found out:

● The Trigger: If you connect your railway tracks to the external map boundary exactly where a Mountain object is already placed, it immediately corrupts the mountain grid in that area.

● The Bug & Desync Effect: If your mountain objects are placed tightly together with no gaps, simply lifting an object and cancelling the action (with the red 'X') will snap it back into place safely. However, if you actually remove or store the object (for example, to use it in a Design Challenge), the gap left behind mathematically shrinks by a fraction (about half a tile). It then becomes impossible to place the exact same object back into its original spot (the green checkmark greys out).

● The Proof (Frosty Fjords): I tested this in my Frosty Fjords region. On the summer side (where a mountain object sits at the track exit), the grid is bugged. On the winter side (where no mountain object sits at the track exit), mountain objects can be lifted, removed, and placed perfectly fine.

● The Fix (Capital City): As soon as I deleted the external track connection in my Capital City, the grid immediately fixed itself. All bugged behavior vanished, and I was able to move all my mountain objects tightly together again without any issues.

● Further Observations: In the Capital City, it is possible to bypass this issue by routing the external connection away from the Mountain zone. However, in Frosty Fjords, there is no alternative route, making this bug unavoidable if you want an external connection there. (Side note: The Beach zone is naturally unaffected by this phenomenon, as external 'connections do not intersect with the beach area).

Conclusion:

The external track connections clearly have a bounding box conflict with existing Mountain assets. Connecting the railway to the outside compresses and corrupts the adjacent mountain building grid until the track is removed.

Attached Screenshots for Reference:

Pic 1: The empty spot visually showing 4 available tiles.

Pic 2 & 3: Trying to place a 4-tile object (aligning left and right) – placement is blocked(no green checkmark).

Pic 4: Trying a 3-tile object on the exact same spot – placement is allowed (greencheckmark appears).

Pic 5: The 3-tile object successfully placed, clearly showing the bugged, unbuildable gapleft behind.