Disable J reuse for operator-based W (Krylov solvers)

WOperator and AbstractSciMLOperator wrap J internally for Krylov
solvers. A stale J degrades Krylov convergence, causing order loss
(e.g. Rodas5P+Enzyme+KrylovJL dropping from order 5 to 1.7).
Always recompute J for these W types.

Co-Authored-By: Chris Rackauckas <accounts@chrisrackauckas.com>

Author: ChrisRackauckas

lib/OrdinaryDiffEqDifferentiation/src/derivative_utils.jl

@@ -54,6 +54,13 @@ function _rosenbrock_jac_reuse_decision(integrator, cache, dtgamma)
         return (true, true)
     end
 
+    # Operator-based W (WOperator for Krylov solvers, AbstractSciMLOperator):
+    # always recompute. Krylov convergence depends on W quality, and stale J
+    # in the operator causes convergence degradation.
+    if cache.W isa WOperator || cache.W isa AbstractSciMLOperator
+        return (true, true)
+    end
+
     # Linear problems: J is constant, never needs recomputation after first eval.
     # But W still depends on dtgamma, so always rebuild W.
     islin, _ = islinearfunction(integrator)