checkpointing in InterpolatingAdjoint seems to be the issue

src/callback_tracking.jl

@@ -266,8 +266,7 @@ function _setup_reverse_callbacks(cb::Union{ContinuousCallback, DiscreteCallback
         # if save_positions[2] = false, then the right limit is not saved. Thus, for
         # the QuadratureAdjoint we would need to lift y from the left to the right limit.
         # However, one also needs to update dgrad later on.
-        if (sensealg isa QuadratureAdjoint && !cb.save_positions[2]) # || (sensealg isa InterpolatingAdjoint && ischeckpointing(sensealg))
-            # lifting for InterpolatingAdjoint is not needed anymore. Callback is already applied.
+        if (sensealg isa QuadratureAdjoint && !cb.save_positions[2]) || (sensealg isa InterpolatingAdjoint && ischeckpointing(sensealg))
             w(y, y, integrator.p, integrator.t)
         end