the woman does not know that the habit of the other woman differs from the habit of her other close relatives who meet the first condition. However, there is no problem if the difference is very little such that it cannot really be counted.
The same rule applies to a woman who has a habit of time and does not experience bleeding at all on the days of her habit but experiences bleeding at other times which lasts for more than ten days, and she cannot distinguish the duration of ḥayḍ by means of its attributes.