Memory runs out while fetching a very long thread

Trying to fetch a post over OStatus that has a lot (huge lot) of replies results into pleroma running out of the memory while processing all of them.

Example of a post triggering this behavior: https://gs.kawa-kun.com/notice/4459821

Erlang dump of the crash: erl_crash.dump-180430.gz

Edit by lain: This is not ostatus specific.