Hello,
while searching for an answer to an Nginx OSCP problem I came across this thread:
The thread has some posts, but nothing that really addresses OP's issue.
In the meanwhile I've resolved my issue and I think that I have a pretty good idea what causes OP's issue as well.
I think that my answer would help others who also find that thread.
Unfortunately I can't post anything there because that thread was auto-closed after 30 days.
Thus it would be great if a moderator could re-open that thread again!