Facter throws noisy "No resolver for external facts file" warning on custom fact files

Puppet Version: 6.13.0
Puppet Server Version: 6.9.0
OS Name/Version: RHEL7

After upgrading to version 6.13.0 of puppet-agent (which includes facter 3.14.8) we have started seeing a "No resolver for external facts file {filename}" warning message for every file in our custom facts directory (/opt/puppetlabs/facter/facts.d), both when running puppet agent -t, as well as running facter directly.

$ puppet agent -t

Warning: Facter: skipping file "/opt/puppetlabs/facter/facts.d/customfact.rb": No resolver for external facts file /opt/puppetlabs/facter/facts.d/customfact.rb

...

Info: Using configured environment 'development'

Info: Retrieving pluginfacts

Info: Retrieving plugin

Info: Retrieving locales

Info: Loading facts

Warning: Facter: skipping file "/opt/puppetlabs/facter/facts.d/customfact.rb": No resolver for external facts file /opt/puppetlabs/facter/facts.d/customfact.rb

...

Info: Caching catalog for myserver.my.domain

Info: Applying configuration version '1582828949'

$ facter hostname

2020-02-27 13:56:50.591690 WARN  puppetlabs.facter - skipping file "/opt/puppetlabs/facter/facts.d/customfact.rb": No resolver for external facts file /opt/puppetlabs/facter/facts.d/customfact.rb

myserver

 All files in our facts.d directory have .rb extensions and 644 permissions (non-executable)

Further research indicates that this does not occur in puppet-agent 6.12.0 with facter 3.14.7, as the message at the time was a debug message "checking execution on {filename}"...

It looks like the relevant change was made here.

We can prevent facter from attempting to load external facts by setting no-external=true in facter.conf, but this does not have any impact on the output of our puppet runs (likely due to using the facter API?)

Desired Behavior:

I would prefer to revert to the previous behavior where our custom facts load successfully without the noisy warning messages. I would prefer not to adjust our verbosity to avoid missing real warnings.

It seems to me that facter should only attempt to load the external facts if the files are executable?

Actual Behavior:

The warnings cause our puppet runs to be unnecessarily noisy.