(Dataflow) Python AfterProcessingTime fires before defined time

https://stackoverflow.com/questions/56700913/why-my-data-in-apache-beam-is-emitted-after-a-few-minutes-instead-of-10h

User on StackOverflow has a problem that AfterProcessingTime on global window fires before allocated time (10h). It dumps events within first minutes/seconds and then drops the rest due to window closed.

Code user provided seems valid. I tried to verify time units accepted by the method, but I couldn't track it all the way through the code.