Is it permissible for a congregant to hold the Mushaf behind the Imam during Tarawih prayer?

It is preferable for the congregant not to hold a Mushaf (copy of the Qur'an) during Tarawih prayers. Instead, they should listen attentively to the Imam's recitation and show humility, because holding the Mushaf distracts the worshipper from the Sunnah acts and may distract their heart and eyes from listening to the Imam and reviewing the verses.

If the Imam makes a mistake and no one prompts him, this only matters if it is in the Fatihah. As for other parts of the prayer, it does not matter if it is left uncorrected, provided there is no one to prompt him. If only one person holds a Mushaf to prompt the Imam when needed, there is no harm in that. However, for everyone to hold a Mushaf is contrary to the Sunnah.

Moreover, this action is not advisable; it is better to focus on the prayer and show humility, placing one's hands on the chest and contemplating what the Imam recites, in compliance with the words of Allah Almighty: "And when the Qur'an is recited, then listen to it and pay attention that you may receive mercy." And with His words, glorified be He: "Certainly will the believers prosper, they who are during their prayer humbly submissive." And the saying of the Prophet, peace be upon him: "The Imam is appointed to be followed, so when he says takbir, say takbir, and when he recites, listen attentively."