Abu Sulayman Malik bin Huwayrith came to our mosque and said, "By Allah, I am about to pray, though I do not actually intend the prayer itself. I only wish to show you how I saw the Prophet ﷺ pray."Then, in the first rakah, when he raised his head from the final prostration, he sat briefly before standing up.
حدثنا إسماعيل حدثنا أيوب
جاء أبو سليمان مالك بن الحويرث إلى مسجدنا فقال والله إني لأصلي وما أريد الصلاة ولكني أريد أن أريكم كيف رأيت النبي ﷺ يصلي قال فقعد في الركعة الأولى حين رفع رأسه من السجدة الأخيرة ثم قام
Its isnad is sahih, like the one before it. The hadith was narrated by Bukhari in similar wording in the chapter on the adhan, on one who leads people in prayer while not intending it, and by Nasai (2/233, no. 1151) with its exact wording in the chapter on tatbiq, on sitting up straight.