I am the scrum master for a team of 6 developers, incl PO. Our manager is a former engineer/developer. We have a very good relationship with him and I am not aware of any real conflicts with him (or really any in the group).
However, he sometimes misses the development part of his role and feels a bit excluded from the team. For a long time, he was unhappy with the fact that I would not invite him to our retros. After several discussions, he has accepted it and understands the reason.
During the last few weeks, he had some time available and was reading up on the technical documentation of the frameworks we use. He has gained some good knowledge about it, but it is very selective. During that time, he started making suggestions on how we could improve the way we use that framework. Initially, they were good ideas, but they turned into the "I have a hammer, everything is a nail" view very quickly. Especially newer team members spent a lot of time looking into his suggestions which mostly didn't lead anywhere.
It's great that our manager has an interest in what we do. However, it makes me feel uneasy to have a developer, who is also your boss, with a limited knowledge base making suggestions on how to do our work. I find it hard to put into words, what exactly my problem with this is.
Does anyone have any experience with such a situation?