apport-cli and cowbuilder fail with cert and keyring errors

Description: Ubuntu 18.04 LTS
Release: 18.04
ubuntu-keyring: Installed: 2018.02.28
apport: Installed: 2.20.9-0ubuntu7.2
cowbuilder: Installed: 0.86

On a bionic system when attempting to report what I suspect is a bug in ubuntu-keying I got the following error

start capture---------------------------------------------------------
$ apport-cli ubuntu-keyring

*** Collecting problem information

The collected information can be sent to the developers to improve the
application. This might take a few minutes.
.....

*** Send problem report to the developers?

After the problem report has been sent, please fill out the form in the
automatically opened web browser.

What would you like to do? Your options are:
  S: Send report (1.2 KB)
  V: View report
  K: Keep report file for sending later or copying to somewhere else
  I: Cancel and ignore future crashes of this program version
  C: Cancel
Please choose (S/V/K/I/C): s

*** Uploading problem information

The collected information is being sent to the bug tracking system.
This might take a few minutes.

*** Error: Network problem

Cannot connect to crash database, please check your Internet connection.

<urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:833)>

Press any key to continue...
end capture-----------------------------------------------------------

I worked around the problem by K'eeping the report and copying it to a Xenial system. From there I am submitting this bug report.

The original problem that caused me to attempt to file a bug report against ubuntu-keyring was an attempt to build a bionic chroot for package building with the following command:

start capture---------------------------------------------------------
# DIST=bionic cowbuilder --create --distribution bionic --components "main universe" --basepath /var/cache/pbuilder/base-bionic-amd64-test.cow --mirror http://us.archive.ubuntu.com:80/ubuntu --debootstrapopts --keyring=/usr/share/keyrings/ubuntu-archive-keyring.gpg
I: Invoking pbuilder
I: forking: pbuilder create --components 'main universe' --debootstrapopts --keyring=/usr/share/keyrings/ubuntu-archive-keyring.gpg --buildplace /var/cache/pbuilder/base-bionic-amd64-test.cow --mirror http://us.archive.ubuntu.com:80/ubuntu --distribution bionic --no-targz --extrapackages cowdancer
W: /root/.pbuilderrc does not exist
I: Running in no-targz mode
I: Distribution is bionic.
I: Current time: Mon Jun 11 22:44:21 UTC 2018
I: pbuilder-time-stamp: 1528757061
I: Building the build environment
I: running debootstrap
/usr/sbin/debootstrap
I: Retrieving InRelease
I: Checking Release signature
E: Release signed by unknown key (key id 3B4FE6ACC0B21F32)
E: debootstrap failed
E: Tail of debootstrap.log:
gpgv: Signature made Thu Apr 26 23:38:40 2018 UTC
gpgv: using RSA key 3B4FE6ACC0B21F32
gpgv: Can't check signature: No public key
E: End of debootstrap.log
W: Aborting with an error
E: pbuilder create failed
I: forking: rm -rf /var/cache/pbuilder/base-bionic-amd64-test.cow
end capture-----------------------------------------------------------

On the same system the following command succeeds:

start capture---------------------------------------------------------
DIST=xenial cowbuilder --create --distribution xenial \
  --components "main universe" \
  --basepath /var/cache/pbuilder/base-xenial-amd64.cow \
  --mirror http://us.archive.ubuntu.com:80/ubuntu \
  --debootstrapopts --keyring=/usr/share/keyrings/ubuntu-archive-keyring.gpg
end capture-----------------------------------------------------------

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubuntu-keyring 2018.02.28 [modified: usr/share/keyrings/ubuntu-archive-keyring.gpg]
ProcVersionSignature: Ubuntu 4.15.0-22.24-generic 4.15.17
Uname: Linux 4.15.0-22-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.2
Architecture: amd64
Date: Mon Jun 11 22:51:48 2018
Dependencies:

PackageArchitecture: all
ProcEnviron:
 LANG=en_US.UTF-8
 TERM=xterm
 SHELL=/bin/bash
 PATH=(custom, no user)
SourcePackage: ubuntu-keyring
UpgradeStatus: No upgrade log present (probably fresh install)