I might be wrong about this, but I think that Python Context Tagging isn't quite working right in the RC2 (also going back to 2200003). To reproduce - create a new python file (either explicitly or by automatic and naming the file with .py). Then type in the new file:
import os
os.chd (this should bring up auto complete for chdir, but it doesn't. chdir is a function not explicitly declared in a .py file)
It does still work correctly in SE2016 however.