No Callbacks on FATAL

I'm developing a module that implements Haskell as a procedural language (
https://www.postgresql.org/about/news/plhaskell-v10-released-2519/)

I'm using a callback function that is called when a memory context is
deleted to remove a temporary file. This works fine when the transaction
ends normally or raises an ERROR. However, when a FATAL event happens, the
callback is not run. Is this a bug or intended behaviour? I think that this
is a new behavior and that the callback was called in an earlier version
(perhaps v14) when I was originally developing this code. I'm running
v15.1.

It seems to me that callbacks should be run in the event of a FATAL event
in order to clean up any lingering issues.
-Ed