Assalamualaikum,
When one is reading namaaz with the niyat of nafl behind an Imam who is leading Farz, then is it permissible for him to give luqma to the Imam?
الجواب وباللہ التوفیق
One should not haste in giving the prompt as long as possible though a person joining Fard Salat Jamaa’t with the intention of Nafil may, per need, prompt the Imam who is leading Fard Salat. There would be no disruption in Salat due to him prompting.
فالحاصل أن الصحیح من المذہب أن الفتح علی إمامہ لایوجب فساد صلاۃ أحد لا الفاتح ولا الاٰخذ مطلقاً في کل حال۔ (البحر الرائق ۲؍۶)
واللہ اعلم بالصواب