brew cask upgrade C1 C2 only lists the first cask (C1) in initial upgrade message

[leonklingele]

General troubleshooting steps

• I understand that if I ignore these instructions, my issue may be closed without review.
• I have retried my command with --force.
• I ran brew update-reset && brew update and retried my command.
• I ran brew doctor, fixed as many issues as possible and retried my command.
• I have checked the instructions for reporting bugs.
• I made doubly sure this is not a checksum does not match error.

Description of issue

I ran brew cask upgrade atom postman, yet only one of the two outdated packages was reported in the initial upgrade message (but both casks were upgraded in the end):

$ brew cask upgrade atom postman
==> Upgrading 2 outdated packages:
atom 1.36.1 -> 1.37.0
[..]

What I expected to see:

==> Upgrading 2 outdated packages:
atom 1.36.1 -> 1.37.0, postman a.b.c -> x.y.z
[..]

Command that failed

See above.

Output of command with --force --verbose --debug

Same as above.

Output of brew cask doctor

==> Homebrew Version
2.1.3-7-g7f4aefe
==> macOS
10.11.6
==> SIP
Disabled
==> Java
12.0.1, 1.8.0_25, 1.7.0_71
==> Gatekeeper support
Enabled
==> Homebrew Cask Install Location
<NONE>
==> Homebrew Cask Staging Location
/usr/local/Caskroom
==> Homebrew Cask Taps:
/usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask (3622 casks)
/usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask-drivers (140 casks)
[..]
==> Environment Variables
HOMEBREW_CASK_OPTS="--appdir=/Applications/Stuff"
LC_ALL="en_US.UTF-8"
PATH="/usr/local/Homebrew/Library/Homebrew/shims/scm:/usr/bin:/bin:/usr/sbin:/sbin"
SHELL="/usr/local/bin/bash"

Output of brew tap

homebrew/bundle
homebrew/cask
homebrew/cask-drivers
homebrew/core
homebrew/services

[leonklingele]

This only affects brew cask upgrade, brew upgrade properly reports the packages about to be upgraded:

$ brew upgrade quilt youtube-dl
==> Upgrading 2 outdated packages:
quilt 0.65 -> 0.66, youtube-dl 2019.05.11 -> 2019.05.20