Aaron Jensen I'm willing to spend the 20 hours of personal time that I think will be required to fix this, if you and/or your company are willing to commit to contribute 20 hours to help the Jenkins project.
Refer to "Jenkins needs you" for suggestions and ideas that will help the project. As a specific example, there are many git plugin bugs which haven't yet been confirmed are actual bugs. As part of your 20 hours, you could review the description of bugs, confirm with testing that they are bugs, and note what you learned on the specific bug report.
If you prefer a view that is more centered on code, consider the suggestions in a "Beginner's Guide to Contributing".
Let me know if you're willing to commit to those 20 hours and I'll plan to start work on it during my Thanksgiving break.
As an alternate, you could fork the git plugin, revert the change that is thought to cause the issue, build the plugin, and use your fork of the plugin (assuming that you don't need the use case covered by that change). You'll then need to do that same work each time you upgrade the plugin until the issue is resolved.