Sorry for delay – was it working before with the same config? What plugin do you use for object caching?
I am using the WP Object Cache by Till Krüss. It is a bit wired, it tried it on different installs on the server, sometimes it works as expected, sometimes it stucks on Redis.
Unfortunately I could not reproduce it – at least with my setup, on servers where I have redis – it just works.. To test, if Redis is working at all – plugin stores one small value inside the object cache. Later, after few benchmarks – it tries to read that small value back. If value is missing – plugin considers, that object cache is not working as it should and do not try to benchmark it at all..
