diff --git a/Library/Homebrew/test/bundle/dumper_spec.rb b/Library/Homebrew/test/bundle/dumper_spec.rb
index 76214fb539431..8ee194523b55a 100644
--- a/Library/Homebrew/test/bundle/dumper_spec.rb
+++ b/Library/Homebrew/test/bundle/dumper_spec.rb
@@ -47,6 +47,12 @@
     allow(Tap).to receive(:select).and_return([])
   end
 
+  # `Tap.taps` and `Cask.casks` memoise the stubbed doubles, which must not outlive the example.
+  after do
+    Homebrew::Bundle::Tap.reset!
+    Homebrew::Bundle::Cask.reset!
+  end
+
   it "generates output" do
     expect(dumper.build_brewfile(
              describe: false, no_restart: false, formulae: true, taps: true, casks: true,
diff --git a/Library/Homebrew/test/bundle/tap_spec.rb b/Library/Homebrew/test/bundle/tap_spec.rb
index 4b3c9fc3a008f..8408328cbed3c 100644
--- a/Library/Homebrew/test/bundle/tap_spec.rb
+++ b/Library/Homebrew/test/bundle/tap_spec.rb
@@ -6,6 +6,11 @@
 require "bundle/tap"
 
 RSpec.describe Homebrew::Bundle::Tap do
+  # `taps` memoises the stubbed `Tap` doubles, which must not outlive the example.
+  after do
+    described_class.reset!
+  end
+
   describe "dumping" do
     subject(:dumper) { described_class }