> That may be my fault. I'm not quite sure. Can your try the latest
> development branch of nginx_upstream_check_module(
> https://github.com/yaoweibin/nginx_upstream_check_module/tree/development)?

Actually since I posted this question, we've been unable to reproduce the condition, no matter how hard we try.

If we can reproduce the condition, I will try that branch. I still need to redeploy with your check_status page patch.