Stuck at "Cleaning... X files" for long periods of time

[user062]

Ninja version:1.12.0
OS: Archlinux

Whenever I run ninja to build a project, it gets stuck at Cleaning... X files for a long period of time (sometimes up to 5 minutes) even when there are no files to clean.
While it is stuck, there is 0 CPU usage, so it's not doing anything.

htop shows that a spawned process is in a zombie state waiting to be reaped:

Here is a related meson report: mesonbuild/meson#10645

I appreciate any help debugging this further.

Thanks a lot.