Must one repeat the Isha prayer that was performed with the same ablution as the Maghrib prayer, given that no blood was noticed until after wiping with toilet paper, where a yellowish-red color appeared?

If a woman experiences bleeding, yellowish discharge, or brownish discharge outside of her regular menstrual period, this nullifies her ablution (wudu'). If this discharge is continuous, she falls under the ruling of a woman experiencing irregular bleeding (mustahadah). In this case, she must perform ablution for each prayer after its time has begun. This obligation applies only if some discharge occurs. If no discharge occurs, her ablution remains valid, and she can pray the subsequent prayer with it.

Al-Buhuti said: "She performs ablution for the beginning of every prayer's time if something (discharge) exits." Ibn 'Uthaymin said: "If nothing exits from her, she remains upon her initial ablution."

If she knows that blood or other discharge is exiting, then she is obligated to perform ablution for each prayer, or to ensure that nothing has exited so she can pray the next prayer with the same ablution. If she does not ascertain this and sees yellowish discharge after the prayer, the more probable opinion is that it was present before the prayer, and she must repeat that prayer.