@ny2 that's what is happening to my Indian colleagues waiting for green card with 140 approval. They're stuck in same position for many years more than 5 yrs . I am also in your position waiting for GC and my corporate legal said the same thing.

Let me try to explain little more , The concept is they did labor certification on that position and it got passed because no us citizen or pr holder applied, and based on that labor your 140 gets approved and thus 485. Now if you move your job or your job role is different then what's the purpose of your labor. The new role you got when your 485 got approved was never labor tested. So it might differ for company to company and how they put job description on your promoted position , and why a company will have two positions for example engineer , Sr engineer with same job role and responsibilities, you can talk to your lawyer also . if you thing it's wrong suggestion then it's fine.