FWIW here are my thoughts on this case.
1. Under the "rules" of AC21 - which are actually very ill defined - you don't technically ever need to work for the GC sponsoring company because the GC is issued on the basis of a FUTURE JOB OFFER, which USCIS expects you to take up once you receive your I-485 approval. So long as your I-485 takes longer than 180 days to be approved, you are free to switch employers as long as the job is substantially the same as the original offer. (I could see how a change of job title might be a problem here.) What is not clear is whether you had a duty to notify USCIS at the time of the job change.
2. Just because USCIS did not immediately recommend your N-400 for approval does not in any way mean you will automatically be denied. From what I've ready here, its not unusual for some IOs to tick the "a decision cannot be made" box even when everything is in order. All cases get reviewed by a second officer before final approval, so maybe you just need to wait and see.
1. Under the "rules" of AC21 - which are actually very ill defined - you don't technically ever need to work for the GC sponsoring company because the GC is issued on the basis of a FUTURE JOB OFFER, which USCIS expects you to take up once you receive your I-485 approval. So long as your I-485 takes longer than 180 days to be approved, you are free to switch employers as long as the job is substantially the same as the original offer. (I could see how a change of job title might be a problem here.) What is not clear is whether you had a duty to notify USCIS at the time of the job change.
2. Just because USCIS did not immediately recommend your N-400 for approval does not in any way mean you will automatically be denied. From what I've ready here, its not unusual for some IOs to tick the "a decision cannot be made" box even when everything is in order. All cases get reviewed by a second officer before final approval, so maybe you just need to wait and see.
Sorry if my posts caused you any worry.