What causes a match-3 board generated with pre-existing matches?

Initial tiles are assigned fully random colors with no constraint, so by chance the starting grid contains runs of three that resolve the instant play begins.

How do I catch this when it only happens for some players?

Capture it automatically from the player's device with the full stack trace, the device and OS, the build, and a breadcrumb trail of what they did. That turns a vague complaint into a specific, reproducible issue you can fix without owning the hardware it happens on.

How to Fix a Match-3 Board Generated With Pre-Existing Matches

Quick answer: When filling each cell, exclude colors that would complete a horizontal or vertical run of three with the two cells already placed to its left or above it.

A new board should require the player to make the first match. If it auto-clears on load, you generated runs of three by pure chance. Constrain generation so no line of three exists at the start.

How to fix it

1. Reject the matching color per cell

As you fill left-to-right, top-to-bottom, look at the two cells to the left and the two above. Build a forbidden set of colors that would form a three-in-a-row and pick from the remaining colors.

2. Re-roll if no color is safe

In rare layouts every color is forbidden for a cell. Re-roll a nearby cell or restart that row rather than placing a match; with enough colors this is rare.

3. Verify the final board has zero matches

After generation, run your normal match detector once. If it finds anything, regenerate; this guards against edge cases in the per-cell logic.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every HTML5 error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.

Reproduce it once with full context and the fix writes itself. The hunt is the expensive part.