AS: plugin's NPAPI methods can not be loaded in Safari 8.0 - OS X Yosemite
May be: Safari 8.0 has bug with loading of NAPAI modules. More info is here.
https://forums.lastpass.com/viewtopic.php?f=7&t=148265&p=496215&hilit=NPAPI
Based on the last info, Safari 8.x and latest does not support NPAPI. The support for this browser will be stopped.
GOOD NEW: The support for this browser will be continuous.