I'm having the same problem since upgrading to 4.8

The bizarre thing is that when I play music through the android app it gets scrobbled correctly (and appears in the log), but when playing through the web interface I only get "listening to..." events in the log, no song submissions or mentions of subsonic trying to submit...
EDIT: fixedAfter testing scrobbling through minisub (which works) I figured it could be a problem with the player instance that was used for playback in chrome.
Deleting my web player (settings>players) and letting subsonic recreate one (I had to restart subsonic/switch browser for it to appear in chrome) fixed the scrobbling issue!
Hope this helps!