There are tools to help you with multi repo GitHub issue management. A little bit of a plug but https://codetree.com is built to solve your exact problem - we sync up milestones (and labels) across many repos and allow you to visualize and work with cross-repo issues in either kanban or list view.
saltcured|8 years ago
With open source, it can be frustrating when other loosely coupled teams and silos have a dependency for a release, but their overall issue-tracking process is mostly an abandoned in place mock-up or fiction. If their repo is included in our board, their issues show up as noise across the whole pipeline. You start remembering to ignore certain issues that you know don't reflect reality, then ignoring everything for certain assignees or reporters, and eventually decide to toggle off their repo from your board view.