Sahaba forgot how to pray
Mawla Ali reminded sahaba how to pray
Musnad Ahmed v15 page 85 hadith 19837
I and Imran b. Husain prayed behind Ali ibn Abu, Talib. He recited takbir when he prostrated, and he recited takbir when he raised his head and he recited takbir while rising up (from the sitting position at the end of two rak’ahs). When we had finished our prayer, ‘Imran caught hold of my hand and said: He has led prayer like Muhammad's prayer (saww) or he said: He has reminded me of the prayer of Muhammad (saww)
Sahih
Sahih al-Bukhari 786
Narrated Mutarrif bin `Abdullah:`Imran bin Husain and I offered the prayer behind `Ali bin Abi Talib. When `Ali prostrated, he said the Takbir, when he raised his head, he said the Takbir and when he got up for the third rak`a he said the Takbir. On completion of the prayer `Imran took my hand and said, "This (i.e. `Ali) made me remember the prayer of Muhammad" Or he said, "He led us in a prayer like that of Muhammad."
Sahaba forgot how to pray
Sahih al-Bukhari 650
I heard Um Ad-Darda' saying, "Abu Ad-Darda' entered the house in an angry mood. I said to him. 'What makes you angry?' He replied, 'By Allah! I do not find the followers of Muhammad doing those good things (which they used to do before) except the offering of congregational prayer." (This happened in the last days of Abu Ad-Darda' during the rule of `Uthman) .
Bukhari 530
"I do not know anything which I used to know during the life-time of Allah's Apostle except this prayer which is being lost (not offered as it should be)
Bukhari 529
Anas said, "I do not find (now-a-days) things as they were (practiced) at the time of the Prophet." Somebody said "The prayer (is as it was.)" Anas said, "Have you not done in the prayer what you have done?