I've worked in a team that had a customer, a product owner, a product manager, a project manager, a scrum master, a senior developer, a junior developer, and a tester. I still have no idea why the company wanted to double up on management. The problems had started from the beginning. The product manager spent little to no time obtaining requirements from the customer, they allowed the customer to outsource the designs and then failed to engage them when it came to determining how the designs worked (i.e., the user stories). Note that even without the requirements, the timeframes were already set and provided to the customer. After the "initial" designed were delivered, the product owner and project manager vanished. The requirements gathering was left as a task for the project manager and scrum master; Neither of which wanted to engage the customer to determine the user stories - they made up their own based on how they they thought the app would work.
The developers were introduced to the project. They were shown the designs, and the project manager and scrum master started dividing the "user stories" between the developers. Note that the user stories contained the HEADING ONLY for a feature (i.e., "Show Page" or "Carousel"). The developers were then asked to "estimate" how long it would take to implement each story. The junior developer started to give time frames. I said that it was bullshit. I explained to them that the user stories should cover every aspect of the how the user interacts with the user - not just a title for something they've seen in a design. I told them that this must be a joke. I'll also take this time to say that I was the senior developer (yes a cynical developer who hates management).
Anyway, we were told that we should just start writing the app as their plan was to give the app to the customer often and then "capture" the changes as needed. Needless to say that the project has been going for over half a year, it was due to go to end user testing almost 3 weeks ago, as we're still getting change requests. We also haven't yet got an API to talk to, so everything we have done that requires data has been done with made up data. Note also that the developer that is writing the API is doing it in a way that doesn't allow any collaboration with the app developers due to the fact that there is no time to do it, so once we get the API, we're going to have to go through the code and either change everything that referenced our "fake" data, or have code in place that translates the real API data format into our made up format.
So to summarise, if there is a bad developer in a team the other developers will have to shoulder a bit more work as the code review process should filter out the bad dev's work. But if there is bad management in a team, the product is doomed.