Failed to downconvert metadata to 1.4. for List::MoreUtils

[castaway]

When trying to install List::MoreUtils just now with cpanm:

cpanm (App::cpanminus) 1.7044 on perl 5.032001 built for x86_64-linux-thread-multi
Work directory is /home/castaway/.cpanm/work/1624203866.12513
You have make /usr/bin/make
You have LWP 6.27
You have /bin/tar: tar (GNU tar) 1.34
Copyright (C) 2021 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by John Gilmore and Jay Fenlason.
You have /usr/bin/unzip
Searching List::MoreUtils () on cpanmetadb ...
--> Working on List::MoreUtils
Fetching http://www.cpan.org/authors/id/R/RE/REHSACK/List-MoreUtils-0.430.tar.gz
-> OK
Unpacking List-MoreUtils-0.430.tar.gz
Entering List-MoreUtils-0.430
Checking configure dependencies from META.json
Checking if you have ExtUtils::MakeMaker 6.58 ... Yes (6.82)
Configuring List-MoreUtils-0.430
Running Makefile.PL
Checking whether pureperl is required... no
Checking for cc... x86_64-pc-linux-gnu-gcc
Checking for cc... (cached) x86_64-pc-linux-gnu-gcc
Checking whether perlapi is accessible... Warning: prerequisite List::MoreUtils::XS 0.430 not found.
yes
Checking if your kit is complete...
Looks good
Failed to downconvert metadata to 1.4. Errors:
'apache_2_0' for 'license' does not have a URL scheme (resources -> license) [Validation: 1.4]
-> N/A
-> FAIL Configure failed for List-MoreUtils-0.430. See /home/castaway/.cpanm/work/1624203866.12513/build.log for details.```

[jkeenan]

The error message is generated from within CPAN::Meta::Converter -- but is that the cause of the problem?

[haarg]

I can't reproduce this error. The version of CPAN::Meta being used might help track down the problem.

The error log is rather weird. It shows perl 5.32.1, which shipped with ExtUtils::MakeMaker 7.44. But it reports ExtUtils::MakeMaker 6.82, which means it would have been downgraded.