If you know something will happen it is not an edge case, at least how the word is commonly used. Doesn't matter how often. System A delivering its event after

If you know something will happen it is not an edge case, at least how the word is commonly used. Doesn't matter how often. System A delivering its event after system B may be an edge case. Daylight saving time computations are not handling an edge case but a normal case that happens twice a year.