Original discussion: https://github.com/l3kn/org-fc/issues/43
The way org-fc handles "learning" cards and fixed review intervals is inconsistent.
(length learning-intervals)are considered as "learning" (opposed to "review" cards)
(length learning-intervals)and its interval is set to
Anki seems to use two learning intervals (1min, 10min) and an interval of 4days for cards that "graduated" to the review phase.