Welcome back to the Wefugees Community and thank you for reaching out to us.
First of all, it is completely normal that the immigration office (Ausländerbehörde) is asking for the passport - it is even a necessary requirement to submit it. Please see also the answer in the follwing thread regarding this matter. As far as I know and as the "Ausbildungsduldung" is still a Duldung (toleration) and not a residence permit, they don't print the document into your passport. The respective documents I have seen so far looked similar to the "normal" Duldung (a multi-sided green paper). However, this is only what I observed.
I hope this helps and do not hesitate to get back to us with any further questions.
All the best,