Comment counting logic fails sometimes

Example: http://hnapp.com/?q=police+use+department+wish+list That articles has much more than 3 comments. Some of them might have been "lost" – unavailable in the HN API. But some non-lost comments were not added to the article, e.g.: https://news.ycombinator.com/item?id=8582222

Figure out why it's happening, verify that inserting comments and stories does indeed work in any order, as designed.

Looks like this is happening when a child comment gets added before its parent comment.