Abdullah bin Umar reported,
He was informed of Ayesha's 
statement that part of the Hijr belongs to the House. Ibn Umar said, "By Allah, I believe that if Ayesha heard this from the Messenger of Allah ﷺ, then I believe the Messenger of Allah ﷺ only refrained from touching those two corners because they are not built upon the original foundations of the House, and people only perform tawaf behind the Hijr for that very reason."
Azami 4979
Sahihعن ابن عمر
أنه أخبر بقول عائشة رضي الله عنها إن الحجر بعضه من البيت فقال ابن عمر: والله إني لأظن عائشة إن كانت سمعت هذا من رسول الله ﷺ إني لأظن رسول الله ﷺ لم يترك استلامهما إلا أنهما ليسا على قواعد البيت، ولا طاف الناس وراء الحجر إلا لذلك.
Abu Dawud (1875) narrated it from Makhlad bin Khalid, who said, Abdul-Razzaq narrated to us, who said, Maamar informed us, from Zuhri, from Salim, from Ibn Umar, and he mentioned it.