The following is some Product Management career advice. I've heard this story, or complaint, way too many times from my colleagues in the Product Management space and more recently with a fellow classmate in the MIT course I'm also enrolled in.

The situation is when a Product Manager is still invited to meetings, but they find themselves suddenly a Project Manager (PM) instead of a Product Manager (PM). They are purely focused on running the program board meetings, talking about tasks and execution only. They will own the roadmap, the priorities and vision, and run the daily meetings, but the decisions are happening somewhere else, with other individuals, and usually on another team.

That is usually the moment the role has quietly changed on them, and they are no longer shaping the product.

Influence

What has allowed me to make changes in my current role is making decisions. The ability to say "no", without making enemies is very powerful to have as a Product Manager. The willingness to say, with conviction and a ton of evidence, we are solving the wrong problem.

"Influence comes from being right about things that matter before other people figure it out." -- Influence: The Psychology of Persuasion by Robert B. Cialdini

As humans, we tend to sway too far one way or another, before we end up just right in the middle. I'm not suggesting PM's that find themselves in this situation suddenly become a narcissistic a-----e. I am saying that if you find yourself suddenly a process owner, rather than a decision maker, get back inline with the pain you were solving in the first place for the customer, and start back fixing that problem.