Kubernetes (GKE) Deployment Update Strategy

Requirement: I want to use NFS share as persistent volume and update deployment by performing rolling updates (GKE).

Problem: Persistent disk, volume and NFS share exist and are bound/mounted but when the app code is modified, pushed and built as an image, performing rolling update doesn't update the code.

• Any ideas why?
• Is this recommended update strategy or you'd suggest doing it otherwise?

(note that using persistent volume is hard requirement.)

Thanks in advance!