Debcheck: "Package has a Depends on perl:any which cannot be satisfied"

[Paul Hardy <unifoundry@gmail.com>]

Debcheck on unifont-bin reports "Package has a Depends on perl:any
which cannot be satisfied" for several architectures; see
https://qa.debian.org/debcheck.php?dist=testing&package=unifont:

-------------- begin -----------------
Package has a Depends on perl:any which cannot be satisfied on mipsel.
Package has a Depends on perl:any which cannot be satisfied on s390x.
Package has a Depends on perl:any which cannot be satisfied on armel.
Package has a Depends on perl:any which cannot be satisfied on armhf.
Package has a Depends on perl:any which cannot be satisfied on powerpc.
Package has a Depends on perl:any which cannot be satisfied on i386.
Package has a Depends on perl:any which cannot be satisfied on amd64.
Package has a Depends on perl:any which cannot be satisfied on mips.
Package has a Depends on perl:any which cannot be satisfied on ppc64el.
Package has a Depends on perl:any which cannot be satisfied on arm64.
--------------- end -----------------

Here is the unifont-bin debian/control file entry in the unifont
package https://sources.debian.net/src/unifont/1:9.0.03-1/debian/control/):

-------------- begin -----------------
Package: unifont-bin
Section: x11
Priority: extra
Architecture: any
Depends: xfonts-utils, fontforge, ${shlibs:Depends}, ${misc:Depends},
 ${perl:Depends}, libwx-perl,
 libgd-perl | libgd-gd2-perl | libgd-gd2-noxpm-perl
Suggests: unifont, texinfo
Description: utilities for manipulating GNU Unifont
 etc.
--------------- end -----------------

The Perl Policy Manual, section 4.4.3 recommends using
"${perl:Depends}", which I do
(https://www.debian.org/doc/packaging-manuals/perl-policy/ch-module_packages.html).
The pdebuild log shows that dh_perl is invoked.  The piuparts page
reports unifont-bin as "Successfully Tested"
(https://piuparts.debian.org/stretch/state-successfully-tested.html#unifont-bin):

-------------- begin -----------------
unifont-bin (Paul Hardy <unifoundry@unifoundry.com>)
   dependency xfonts-utils is successfully-tested
   dependency fontforge is successfully-tested
   dependency libc6 is successfully-tested
   dependency perl is successfully-tested
   dependency libwx-perl is successfully-tested
   dependency libgd-perl is successfully-tested
      alternative dependency libgd-gd2-perl is virtual
         provider libgd-perl is successfully-tested
      alternative dependency libgd-gd2-noxpm-perl is virtual
         provider libgd-perl is successfully-tested
--------------- end -----------------

Does anyone know what is causing this Debcheck message, and how can it be fixed?

Thank you,


Paul Hardy