Q: Is praying in congregation after tarawih prayer an innovation?
A: What is known as salat al-ta'qib is not disliked. Ta'qib is prayer performed in congregation after tarawih and witr. This is explicitly mentioned by Imam Ahmad and based on Anas (radi Allahi 'anu) saying, "They are not coming back except for good they hope for", who did not view it as problematic/sinful. It is righteousness and obedience.
This is the case even if one came back before going to sleep or did not delay it to the middle of the night regardless of the break between the two, be it long or short.
Source: Sharh al-Muntah, Kashshaf al-Qina'