For me it appears it is the plugin that is the culprit. I used to get a 92 pagespeed score and now I get a 77. I wish I could just downgrade to the version of this plugin from last year.
Unless it is some error on googles end? but this just started today. Ive had a litany of issues with W3 lately which is a shame. I like the functionality but it has become very unwieldy. Hopefully a fix will arrive soon?
I hate to complain about a free plugin, but this is a concern :-/.