A temporal dead zone
The Daily Problem intro used a timeline before it was declared. It crashed only on the very first load — the kind of bug a quick manual test never hits twice.
Rotating the wrong object
Rotations were applied to groups instead of meshes, so props orbited the wrong pivot. Fixed by building each prop around its own origin.
An empty AI answer
Gemini sometimes returned an empty candidate. The app now validates every generated problem and falls back to a bundled, human-checked library instead of showing a blank screen.
The stale server
The iPad kept showing old problems because of caching. "Regenerate" now bypasses every cache, and a debug panel shows the exact prompt and answer.
Dark theme, light leftovers
Selected pills became unreadable, the avatar turned near-black and answer buttons stayed pastel because colours were computed at load. Fix: resolve colours at use and freeze a separate avatar palette.
Washed-out 3D
Glossy materials plus bright lights burned out the candy palette. I tuned the lights and added a per-theme tint, then checked every change against screenshots.
Text nobody could read
A row of dark-green text on a purple panel only showed up when reviewing 32 screenshots side by side. Contrast is now themed per surface.
A real bug found by QA
Game stages could be torn down twice, logging a WebGL "context already lost" warning. Caught by the automated runs; disposal is now idempotent.
My own test harness
Parallel software-rendered pages starved the CPU and made healthy games look stuck. Moving headless Chrome onto the GPU fixed it — and some "stuck" bot games were just waiting for a child to tap "Got it".
A mistake worth admitting
When a device build timed out, a chained command kept going and installed an old build on my iPad. The fix was boring and important: check every exit code before the next step.
