normadize on "[Plugin: W3 Total Cache] notices - trying to access non-existent object properties"

Well, you can always hack the plugin code to fix it, e.g. suppress the error by using @, but I reported it so that the plugin author fixes it for everyone.

I this case, you can replace $url_block->header->args with @$url_block->header->args on line 115 in /W3/PageSpeed.php, and do the same trick for all other such errors.