If some requirement are regarded as safety attribute, it means that in-achievement of safety requirement leads to threaten safety.
The rationale is explained in the somewhere. I believe that system FTA or system FMEA are proper means of why they are born.
After they are identified, safety engineers shall suggest methods how to handle them. Their suggestions are called safety mechanisms in ISO standard.
Sometimes, engineers forget this simple principle. So non-safety related requirements are mis-perceived as safety requirements.
All safety requirements have birth-registered? Unregistered has a potential to threat safety. Don’t forget to register. It is natural like happened in our society.
Can a project in production development project achieve functional safety requirements when its previous project in the advanced development project doesn’t consider functional safety ?
It is not easy to satisfy functional safety requirements in production project unless being prepared in advanced development project.
Or it will take longer than normal production project.
How to improve this situation?
We can get a hint from SEooC section in the ISO 26262-10, Clause 9
A picture below depicts SEooC development and Item development process
In general, advanced development project starts without customer, so its situation is similar to SEooC development situation. During the project many assumptions are made.
If Advanced Development Project follows like SEooC development process, Production Development Projects might reuse previous results. Additional tasks might be to compare between assumptions and requirements and to bridge gaps.