Carthage fails if dependency changes a tag

• carthage install method: homebrew
• which carthage: /usr/local/bin/carthage
• carthage version: 0.33.0
• xcodebuild -version: Xcode 10.2.1, Build version 10E1001
• Are you using --no-build? no
• Are you using --no-use-binaries? no
• Are you using --use-submodules? no
• Are you using --cache-builds? yes
• Are you using --new-resolver? no

Cartfile

github "instacart/TrueTime.swift"

I'm running /usr/local/bin/carthage outdated --xcode-warnings as part of our build process. Unfortunately this command started failing, which causes our build to fail.

Carthage Output

*** Fetching TrueTime.swift
A shell task (/usr/bin/env git fetch --prune --quiet https://github.com/instacart/TrueTime.swift.git refs/tags/*:refs/tags/* +refs/heads/*:refs/heads/* (launched in /Users/manselm/Library/Caches/org.carthage.CarthageKit/dependencies/TrueTime.swift)) failed with exit code 1

Running the git command to see what's wrong, it looks like the TrueTime folks did something weird with a tag

/usr/bin/env git fetch --prune https://github.com/instacart/TrueTime.swift.git refs/tags/*:refs/tags/* +refs/heads/*:refs/heads/*
From https://github.com/instacart/TrueTime.swift
 ! [rejected]        5.0.1      -> 5.0.1  (would clobber existing tag)

Expected output

Carthage's cache was out of date. It should be able to detect this and refresh its own cache, not fail.