diff --git a/Project.toml b/Project.toml
index 655c4a6..6b3c56c 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "FunctionWrappersWrappers"
 uuid = "77dc65aa-8811-40c2-897b-53d922fa7daf"
 authors = ["Chris Elrod <elrodc@gmail.com> and contributors"]
-version = "1.9.0"
+version = "1.9.1"
 
 [deps]
 FunctionWrappers = "069b7b12-0de2-55c6-9aab-29f3d0a68a2e"
diff --git a/ext/FunctionWrappersWrappersEnzymeExt.jl b/ext/FunctionWrappersWrappersEnzymeExt.jl
index 42229f6..38097c5 100644
--- a/ext/FunctionWrappersWrappersEnzymeExt.jl
+++ b/ext/FunctionWrappersWrappersEnzymeExt.jl
@@ -1,10 +1,26 @@
 module FunctionWrappersWrappersEnzymeExt
 
 using FunctionWrappersWrappers
+using FunctionWrappersWrappers: SingleCacheStorage, DictCacheStorage, NoCacheStorage
 using Enzyme
 using EnzymeCore
 using EnzymeCore.EnzymeRules
 
+# =============================================================================
+# Mark cache-storage types as inactive
+# =============================================================================
+# `SingleCacheStorage` and `DictCacheStorage` are mutable / contain a `Dict`,
+# and their cache-miss branches write to that storage. Without these
+# declarations Enzyme conservatively treats any closure that *might* touch a
+# `FunctionWrappersWrapper` (e.g. via `remake(prob; p = …)` capturing the
+# problem in scope) as potentially writing to the wrapper's cache, and
+# refuses to prove the captured argument read-only. The cache values are
+# `FunctionWrapper`s used purely for dispatch / dynamic call speedup; they
+# never hold derivative data.
+EnzymeCore.EnzymeRules.inactive_type(::Type{<:SingleCacheStorage}) = true
+EnzymeCore.EnzymeRules.inactive_type(::Type{<:DictCacheStorage}) = true
+EnzymeCore.EnzymeRules.inactive_type(::Type{NoCacheStorage}) = true
+
 # =============================================================================
 # Helper: build a Forward mode from FwdConfig flags
 # =============================================================================