According to this comment from Locutus (so the maintainer was informed 
):
https://aur.archlinux.org/packages/prowlarr#comment-941146
This seems to be something else:
==> Validating source_x86_64 files with sha512sums...
prowlarr.master.1.9.4.4039.linux-core-x64.tar.gz ... FAILED
==> ERROR: One or more files did not pass the validity check!
I see also:
I’m also getting that with Radarr
So it shouldn’t be related to the package name changes in my opinion…