I think you mistakenly switched the roles there. You are not isolating a bug for the author. The author is using their software and is happy with its current state. It is you that is being hit by a supposed bug, and you are isolating it for yourself. Then you are expecting the author to do the additional work for you and handle your supposed fixes. Don’t get me wrong, you’re probably both helping each other in the best spirit of open source, but it’s not you who’s the ideal of generosity there.
This a thousand times. If you hit a bug on my code and put together a PR to fix it, the reasons I would merge it are in order of importance:
1. For you, since you are nice and helpful debugging it and fixing it for you and others so I want to make it easy for you to use the working code.
2. For other users that might hit the bug, for every PR bugfix there are likely N people hitting the bug.
3. For me in case I hit it in the future.
4. For correctness sake.
But not all bugs are straightforward, many have side-effects or disadvantages that I might not be comfortable merging straight away. So I have to evaluate how long it'll take me to review the PR and whether it's even worth-it (the vast majority of times PRs are worth-it, but issues are a hit and miss).
I think you mistakenly switched the roles there. You are not isolating a bug for the author. The author is using their software and is happy with its current state. It is you that is being hit by a supposed bug, and you are isolating it for yourself. Then you are expecting the author to do the additional work for you and handle your supposed fixes. Don’t get me wrong, you’re probably both helping each other in the best spirit of open source, but it’s not you who’s the ideal of generosity there.