1) you have to comply with instructions received from your senior in respect of work to be done by you as per your responsibilities
2) if instructions furnished by senior did not relate to your scope of work and related to some other officer you have rightly in your noting pointed out the same .
3) no case of insubordination is made out .
4) in the event any show cause notice is issued to you in your reply mention that you did not comply with instructions since it did not pertain to your work
5) you should also go and meet your senior personally and mention that you have no intentions to defy his instructions and that in your notings you have merely stated correct the correct legal position regarding your responsibilities