I inspected the issue further, 50% of my issues were caused by failed ndb.transaction's - other half was left uncovered for me, but I'm guessing similar issues
I improved things on my end to handle such failures better -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/google-appengine. To view this discussion on the web visit https://groups.google.com/d/msgid/google-appengine/3dfd2868-362c-4a1d-86a2-e57259d86961%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
