GLFW callbacks not working

[nbilyk]

I'm having a strange issue that I'm not sure how to troubleshoot.
Sometimes the GLFW window callbacks aren't getting triggered. Any of them.
Everything else works, the window is created, I can draw like normal, but no callbacks are invoked, not even window close.

Any ideas what I should check? (I'm on Windows 10, I believe it happens in different JDKs)