Pamac can’t find PKGBUILD while yay can

Pamac --version

$ pamac --version
Pamac 10.3.0-6  -  libpamac 11.2.0-13
Copyright © 2019-2022 Guillaume Benoit
This program is free software, you can redistribute it under the terms of the GNU GPL.

Variant in use

CLI

Distribution

Manjaro

Desktop environment

KDE

What's not working

as title. Please see below output

How to reproduce?

$ pamac update
Preparing...
Synchronizing package databases...
Checking frpc dependencies...
Warning: lib32-mesa: local (22.0.0-1) is newer than multilib (21.3.8-2)
Warning: python-pyqt5: local (5.15.6-7.1) is newer than extra (5.15.6-7)
Resolving dependencies...
Checking inter-conflicts...

To build (1):
  frpc  0.42.0-1  (0.41.0-1)  AUR


Edit build files : [e] 
Apply transaction ? [e/y/N] y


Building frp...
==> ERROR: PKGBUILD does not exist.

$ yay -S frpc  
:: Checking for conflicts...
:: Checking for inner conflicts...
[Aur:1]  frp-0.42.0-1 (frpc)

  1 frp (frpc)                               (Installed) (Build Files Exist)
==> Packages to cleanBuild?
==> [N]one [A]ll [Ab]ort [I]nstalled [No]tInstalled or (1 2 3, 1-3, ^4)
==> 
:: (1/1) Downloaded PKGBUILD: frp
  1 frp (frpc)                               (Installed) (Build Files Exist)
==> Diffs to show?
==> [N]one [A]ll [Ab]ort [I]nstalled [No]tInstalled or (1 2 3, 1-3, ^4)
==> n
:: (1/1) Parsing SRCINFO: frp (frpc)
==> Making package: frp 0.42.0-1 (Sun 24 Apr 2022 10:25:25 AM CST)
==> Retrieving sources...
  -> Downloading frp-0.42.0.tar.gz...
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   131    0   131    0     0    210      0 --:--:-- --:--:-- --:--:--   210
100 1250k    0 1250k    0     0   543k      0 --:--:--  0:00:02 --:--:--  836k
==> Validating source files with sha256sums...
    frp-0.42.0.tar.gz ... Passed
==> Making package: frp 0.42.0-1 (Sun 24 Apr 2022 10:25:34 AM CST)
==> Checking runtime dependencies...
==> Checking buildtime dependencies...
==> Retrieving sources...
  -> Found frp-0.42.0.tar.gz
==> Validating source files with sha256sums...
    frp-0.42.0.tar.gz ... Passed
==> Removing existing $srcdir/ directory...
==> Extracting sources...
  -> Extracting frp-0.42.0.tar.gz with bsdtar
==> Sources are ready.
==> Making package: frp 0.42.0-1 (Sun 24 Apr 2022 10:25:48 AM CST)
==> Checking runtime dependencies...
==> Checking buildtime dependencies...
==> WARNING: Using existing $srcdir/ tree
==> Starting build()...

More information (optional)

https://forum.manjaro.org/t/pamac-cant-find-pkgbuild/109233/2?u=lance6716

The PKGBUILD in question is a little special, in the sense that it’s actually one PKGBUILD that builds 2 packages, from 1 source.