Quick answer: Let buttons size to their content with a sensible min-width and padding, and use flexible containers so the longest translation drives the layout instead of clipping.
English fits, German overflows. Designing buttons around the longest reasonable translation rather than the English word prevents clipped or overrunning labels. Here is how.
How to fix it
1. Size buttons to content, not to English
Replace fixed pixel widths with content-driven sizing plus padding and a min-width, so a longer German label expands the button instead of being truncated.
2. Budget 35% expansion in your layouts
Use a rule of thumb that translations run roughly a third longer than English for short strings, and test layouts with that headroom before locking dimensions.
3. Wrap or scale as a controlled fallback
For the rare label that still overflows, allow a second line or a small font auto-shrink with a floor, rather than hard clipping that hides text.
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.