Developer unwilling to share solution of bugfix (issue tracker)

I am not sure why the developer who has the patch is not able to contribute it back. He first says that he is under NDA, then goes on to say that he wants the community to learn or become better at fixing bugs?

Oh well, you come across all kinds of people when you are working on OSS. They have their own motivations for their actions. We just hope that someone who is able to fix it will come along and do it.