It's working for me now with that config file as well so far. I'll keep watching too.

Both my coworker and I have the same issue. We just started using gpg for git commit signing. Works the first time. Then sometime later, no window pops up and will hang git indefinitely because it's waiting on the agent. Kill the agent and gpg process let git error out. try again, gpg-agent window prompting for password shows up and works.