diff --git a/Project.toml b/Project.toml
index 787ebe7f..bcb216f5 100644
--- a/Project.toml
+++ b/Project.toml
@@ -85,10 +85,8 @@ julia = "1.10"
 
 [extras]
 FastBroadcast = "7034ab61-46d4-4ed7-9d0f-46aef9175898"
-ForwardDiff = "f6369f11-7733-5829-9624-2563aa707210"
 KernelAbstractions = "63c18a36-062a-441e-b654-da1e3ab1ce7c"
 Measurements = "eff96d63-e80a-5855-80a2-b1b0885c5ab7"
-Mooncake = "da2b9cff-9c12-43a0-ae48-6db2b0edb7d6"
 MonteCarloMeasurements = "0987c9cc-fe09-11e8-30f0-b96dd679fdca"
 Pkg = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
 Polyester = "f517fe37-dbe3-4b94-8317-1923a5111588"
@@ -101,9 +99,7 @@ StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 StructArrays = "09ab397b-f2b6-538f-b94a-2f83cf4a842a"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
-Tracker = "9f7883ad-71c0-57eb-9f7f-b5c9e6d3789c"
 Unitful = "1986cc42-f94f-5a68-af5c-568840ba703d"
-Zygote = "e88e6eb3-aa80-5325-afca-941959d7151f"
 
 [targets]
-test = ["FastBroadcast", "ForwardDiff", "KernelAbstractions", "Measurements", "Mooncake", "Pkg", "Polyester", "Random", "RecursiveArrayToolsShorthandConstructors", "ReverseDiff", "SafeTestsets", "SciMLTesting", "SparseArrays", "StaticArrays", "Statistics", "StructArrays", "Tables", "Test", "Unitful", "Zygote"]
+test = ["FastBroadcast", "KernelAbstractions", "Measurements", "Pkg", "Polyester", "Random", "RecursiveArrayToolsShorthandConstructors", "SafeTestsets", "SciMLTesting", "SparseArrays", "StaticArrays", "Statistics", "StructArrays", "Tables", "Test", "Unitful"]
diff --git a/src/named_array_partition.jl b/src/named_array_partition.jl
index 887f658e..d88f1c13 100644
--- a/src/named_array_partition.jl
+++ b/src/named_array_partition.jl
@@ -146,7 +146,7 @@ function Base.similar(
     return NamedArrayPartition(similar(ArrayPartition(x)), getfield(x, :names_to_indices))
 end
 
-# when broadcasting with ArrayPartition + another array type, the output is the other array tupe
+# when broadcasting with ArrayPartition + another array type, the output is the other array type
 function Base.BroadcastStyle(
         ::Broadcast.ArrayStyle{NamedArrayPartition}, ::Broadcast.DefaultArrayStyle{1}
     )
diff --git a/test/AD/Project.toml b/test/AD/Project.toml
new file mode 100644
index 00000000..dbbef75e
--- /dev/null
+++ b/test/AD/Project.toml
@@ -0,0 +1,18 @@
+[deps]
+ForwardDiff = "f6369f11-7733-5829-9624-2563aa707210"
+Mooncake = "da2b9cff-9c12-43a0-ae48-6db2b0edb7d6"
+RecursiveArrayTools = "731186ca-8d62-57ce-b412-fbd966d074cd"
+ReverseDiff = "37e2e3b7-166d-5795-8a7a-e32c996b4267"
+Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
+Zygote = "e88e6eb3-aa80-5325-afca-941959d7151f"
+
+[sources]
+RecursiveArrayTools = {path = "../.."}
+
+[compat]
+ForwardDiff = "0.10.38, 1"
+Mooncake = "0.5"
+RecursiveArrayTools = "4"
+ReverseDiff = "1.15"
+Test = "1"
+Zygote = "0.7"
diff --git a/test/Core/adjoints.jl b/test/AD/adjoints.jl
similarity index 100%
rename from test/Core/adjoints.jl
rename to test/AD/adjoints.jl
diff --git a/test/Core/mooncake.jl b/test/AD/mooncake.jl
similarity index 100%
rename from test/Core/mooncake.jl
rename to test/AD/mooncake.jl
diff --git a/test/runtests.jl b/test/runtests.jl
index 33c07597..a0fe285f 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -22,8 +22,6 @@ run_tests(;
         @time @safetestset "Table traits" include("Core/tabletraits.jl")
         @time @safetestset "StaticArrays Tests" include("Core/copy_static_array_test.jl")
         @time @safetestset "Linear Algebra Tests" include("Core/linalg.jl")
-        @time @safetestset "Adjoint Tests" include("Core/adjoints.jl")
-        @time @safetestset "Mooncake Tests" include("Core/mooncake.jl")
         return @time @safetestset "Measurement Tests" include("Core/measurements.jl")
     end,
     groups = Dict(
@@ -70,6 +68,18 @@ run_tests(;
                 return @time @safetestset "JET Tests" include("NoPre/jet_tests.jl")
             end,
         ),
+        # AD lives in its own env (test/AD/Project.toml) so its heavy AD-backend
+        # deps (Mooncake/Zygote/ForwardDiff/ReverseDiff) stay out of the root test
+        # target. It is deliberately absent from `all` and not run in the Downgrade
+        # lane: Mooncake 0.5 requires Julia >= 1.10.8, which the downgrade resolver
+        # cannot satisfy when it minimizes Julia to the 1.10.0 LTS floor.
+        "AD" => (;
+            env = joinpath(@__DIR__, "AD"),
+            body = function ()
+                @time @safetestset "Adjoint Tests" include("AD/adjoints.jl")
+                return @time @safetestset "Mooncake Tests" include("AD/mooncake.jl")
+            end,
+        ),
     ),
     qa = (;
         env = joinpath(@__DIR__, "QA"),
diff --git a/test/test_groups.toml b/test/test_groups.toml
index 2da0790b..ebea6523 100644
--- a/test/test_groups.toml
+++ b/test/test_groups.toml
@@ -18,6 +18,16 @@ num_threads = 2
 versions = ["lts", "1"]
 num_threads = 2
 
+# AD backends (Mooncake/Zygote/ForwardDiff/ReverseDiff) live in their own env
+# (test/AD/Project.toml) and run as their own CI group. in_all = false keeps them
+# out of the "All" aggregate, and the Downgrade lane only runs "Core", so AD is
+# never fed to the downgrade resolver -- Mooncake 0.5 needs Julia >= 1.10.8, which
+# the downgrade resolver cannot place when it minimizes Julia to the 1.10.0 floor.
+[AD]
+versions = ["lts", "1"]
+num_threads = 2
+in_all = false
+
 [GPU]
 versions = ["1"]
 runner = ["self-hosted", "Linux", "X64", "gpu"]