In terms of managers wanting to know the root of a problem, I think it depends on the manager. Most will want to know at some point, after all they're bound to be asked by their bosses. A bad manager will want to know what caused the issue while it's being fixed and you realistically don't have that information, a good manager will let you (and help you) focus on fixing the issue, give you time to analyse the issue afterwards and only then ask what caused it and what can be done to prevent it happening again.

Assuming your manager is responsive to such things (if not there's probably little hope either way), simply telling them there's a problem does little more than put extra work on their desk, so little surprise it might not be appreciated. Giving them one or more solutions at the same time makes things easier for them, and they're far more likely to be receptive to any ideas you might have.

The only issue I have with this idea is that it assumes you're capable of providing a solution, and it's quite possible that won't be the case. I'm quite capable of identifying a problem with an application or something for instance, but I'm not a developer, and I wouldn't know where to start in order to resolve it. The best I can hope to do it provide as much information as possible so someone with the required skills and replicate the issue and fix a solution to it.