@guser39 The developers have many things on their plates. I don't see why they should waste their time finding proof of issues being from upstream. Have you checked out the upstream issue tracker? It's a nightmare to find stuff in it because it's filled with so many issues, many of them duplicates or invalid or just out of place. I'd rather the developers spend their valuable time working on GrapheneOS, not hunting down issues to copy and paste links to.
GrapheneOS developers don't usually fix upstream issues because doing so would be a waste of their valuable time. Also, this specific issue has little to nothing to do with mobile privacy or security. GrapheneOS does sometimes fix some upstream issues, but it doesn't look like this one will be one of them.
Someone already listed different reasons why they could know the issue is from upstream. If an issue isn't linked, it could be that they just simply know that the issue isn't caused by changes made by GrapheneOS. It's not difficult for them to say certain things are upstream bugs when they know they haven't touched any of the relevant code. Even if they do know for sure that there's an issue in the upstream issue tracker, why should they go find it? Upstream issues are upstream devs' problems.
Even if a member of the community did fix this issue, it would still take up GrapheneOS developers' time. They'd have to review the code, very likely have to spend a lot of time doing that and suggesting improvements, etc. Then even after the contributor should maintain the fix in case it breaks after future updates, which would take up even more of the GrapheneOS developers' time. If the contributor just doesn't do that, then GrapheneOS developers then have to maintain the fix themselves. The upstream project should fix the problem.
guser39 Let's say that I was interested in contributing and working on the buggy Bluetooth behavior. At this point, I have no starting point.
If you want to work on this, you can ask in the issue tracker. Part of the point of the issue tracker is to collaborate on identifying and fixing issues. If someone expressed genuine interest in fixing something, the developers will discuss there. But you've already said that you don't have the time to contribute, so please don't ask them for clarification just for your benefit.
Finally, I do have to say that a couple of your responses on here come off as rude. Being rude is no way to get help or to get answers. You say you don't have time to contribute, but instead you come to the forum to complain that the developers didn't provide enough evidence that an issue is from AOSP to satisfy you. This is no way to get answers.