Backends not loading code properly?

[Prateek Malhotra]

I just started getting the following error on launching instances of a backend I have when it tries to hit the '/_ah/start' end point on start up:

...REMOVED...

bq_schema = ndb.JsonProperty('bqs', compressed=True)
  File "/base/python27_runtime/python27_lib/versions/1/google/appengine/ext/ndb/utils.py", line 135, in positional_wrapper
    (wrapped.__name__, max_pos_args, plural_s, len(args)))
TypeError: __init__() takes at most 1 positional argument (2 given)

Followed by:

Process terminated because it failed to respond to the start request with an HTTP status code of 200-299 or 404.

I know for a fact the code its breaking on is ok. My frontend runs the same code and is working fine as well as other backend instances. Looks as if the code for my application isn't being loaded properly on select instances. I target tasks to specific instance numbers of my backend, and although the backend instances that fail will shutdown and try to spin up again, they keep hitting these issues. Every single backend instance that hits this seems to always hit it. So since I am targeting, my tasks never complete.

Was there a tweak made to the platform that could be causing these issues?

Useful Info:

Python 2.7 with threadsafe: True

Backend/Front End code are the same, just using backends for back end work on specific URL end points

Backends were functioning fine for the past few months and just started seeing issues such as this

Backends are 20 dynamic B1 instances

The '/_ah/start' end point doesn't do anything but go through my frameworks start up procedure (imports and such) which hasn't cause any issues in the past.

Any help would be appreciated!

[Prateek Malhotra]

I've posted in the NDB discussion group, but in case any one is wondering.....

In order to fix this, I've had to change my definitions to pass in the 'name' as a named argument:

payload = ndb.JsonProperty(name='p', compressed=True)

Did a silent update to the platform cause this issue? Can it be fixed or was I doing it wrong for months and only now is GAE throwing errors for it?