Does Google App Engine's git Push-to-Deploy also update backends?
No -- It doesn't update backends.
(My cron jobs ran last night and failed because they were running old code.)
Nothin' like good ol' appcfg.py update ./ --backends
When using appcfg.py, I had to specify backends to update them. 
What about when I'm using Push-to-Deploy?
I ask because I see two of my Versions don't have the same "deployed" date -- the backend still says "6 days ago". I didn't change backends.yaml, but I did change the code that runs on that backend. 
Should I see a new "deployed" date? Is git Push-to-Deploy working?