"Every 26 days" is ordinary English for an interval, but it sits directly
beneath a start and an end — a duration — and a reader who has just been
thinking in durations reads it as another one. Naming the shape of the
repetition is what separates them, and "cycle" is the word this genre
already uses.
A cycle of one unit is named rather than numbered, because nobody says "a
1-week cycle"; a longer one takes the singular unit, since a hyphenated
"26-day" is an adjective and not a count. The article follows how the
number sounds — an 8-day cycle, an 11-day, an 84-day — which is the kind of
wrong that reads as sloppiness rather than as a bug.
The manual control becomes "Cycle length" for the same reason: it is asking
for the length of the cycle, not for a duration the reader already gave.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
