I've been working in a particular Agile/Scrum team for about 5 months now, and I am conscious of a specific concern (that's been mentioned to me in private) for a few weeks, from 2 different team members (out of 8). The concern doesn't affect me directly but I recognise that it does affect those team members and it is legitimate, not just a "gripe".
In our last few retro's (where we "anonymously" add things to a board along the theme of "Things that went well" / "Things that didn't go well" or whatever) these concerns haven't been added to the board. I think they are either conflict avoidant (understandable) or think it won't make a difference as it is just "talk for the sake of it" or similar.
I didn't pursue the people but they have independently told me that they have concern X and Y (which are genuine problems). And they don't want to raise it because of thinking the others will lambast them for it, or they won't be perceived as team players any more, or similar.
Could, or should, I raise concern X and Y on our next retro? If they are not things that personally affect me, but I am aware of them as things affecting "the team".
I could speak about why I added them, if asked.