After I update my Magento 2 installation to 2.3.2 from 2.3.1 the site caching seems not working as expected. I've double checked the FPC enabled, the site is in production mode. Still, the first response takes more than 20 seconds to the response. Here is the response header I get.
Any idea what causing this?
Please note: Here I see the expires date is earlier than the current time.
I completely disable the cache, then the loading time takes about 32.x seconds (without caching). With caching enabled it takes 20.x seconds.