Dear @Bossbig,
Welcome back to the Wefugees Community and thank you for reaching out to us again.
As my colleague explained here once, applicants for asylum are obliged to submit their passports to the authorities in case they hold one. Please note that they should not apply for a new passport at i.e. their embassy during the pending asylum procedure!
As far as I know, it can not be ruled out that the "Standesamt" (registry office) contacts the immigration office (Ausländerbehörde) when you start the marrying procedure for exchanging data and information and the relevant authorities subsequently may learn about any not submitted identification document.
Do you agree dear @mbeon-fardeen or @mbeon-Christine and can you add any further information/advice?
In any case, please don't hesitate to get back to us with any more questions.
All the best,
Meike