diff --git a/.github/workflows/Downstream.yml b/.github/workflows/Downstream.yml
index 6c4ec7b41..1c6f9f700 100644
--- a/.github/workflows/Downstream.yml
+++ b/.github/workflows/Downstream.yml
@@ -46,6 +46,8 @@ jobs:
           repository: ${{ matrix.package.user }}/${{ matrix.package.repo }}
           path: downstream
       - name: Load this and run the downstream tests
+        env:
+          JULIA_PKG_PRECOMPILE_AUTO: 0
         shell: julia --color=yes --project=downstream {0}
         run: |
           using Pkg
diff --git a/src/polyform.jl b/src/polyform.jl
index dbc6578e5..a42569169 100644
--- a/src/polyform.jl
+++ b/src/polyform.jl
@@ -418,7 +418,9 @@ function quick_mulmul(x::S, y::S)::Tuple{S, S} where {T <: SymVariant, S <: Basi
 
             return xx, yy
         end
-        _ => _unreachable()
+        # Not `_unreachable` since `adjoint(vec) * vec` can end up here, and we just want
+        # to ignore it.
+        _ => (x, y)
     end
 end
 
diff --git a/test/misc.jl b/test/misc.jl
index d5097b074..dd35c9b94 100644
--- a/test/misc.jl
+++ b/test/misc.jl
@@ -311,3 +311,10 @@ end
     # Test getmetadata with default
     @test SymbolicUtils.getmetadata(x, Float64, "default") == "default"
 end
+
+@testset "`quick_cancel` handles `adjoint(vec) * vec`" begin
+    @syms x[1:3]
+    num = x[1] * x[2]
+    den = x'x
+    @test isequal(quick_cancel(num, den), (num, den))
+end