Isn't it ironic that Sentry is one of the tools mentioned in py2->py3 migration? (Sentry is on py2 and as far as I remember they were not very optimistic about migrating)
not to pick on sentry here, but you know, my experience is that people are having a hard time migrating due to them using obscure tricks and features of python 2.7. so their code is breaking because the language evolved.
the saying goes write dumb code or something because debugging is twice as hard. if there is anything to learn from all this, it's to write dumb code because maintenance is twice as hard too.
that's all that is happening really!