I just upgrade Nginx-Helper from 1.9.7 to 1.9.9 , after that when I update a post the cache purge doesn’t work anymore.
I use fastcgi cache, and it works fine in version 1.9.7
My wordpress permalink setting is /%category%/%postname%
Dig Into log file, I notice that in 1.9.7 it purged URL /%category%/%postname% , but in 1.9.9(and 1.9.8) it purge /%category%/%postname%/ (with trailing slash) so the purging url seems doesn’t work right.