It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) "used to shorten the prayer in the valley of al-Aqiq."
This hadith is not narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) as a marfu' (Prophetic) report except with this chain.
Hadith Referenceالمعجم الأوسط / باب الألف / 2956
Hadith Takhrij«أخرجه الطبراني فى «الصغير» برقم: 843، والطبراني فى «الأوسط» برقم: 7921، 9239»