diff --git a/docs/source/conf.py b/docs/source/conf.py
index 373a0999c..24f3ade7b 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -20,7 +20,7 @@
     "Daria Van Hende <dvanhende@oxfordquantumcircuits.com>, "
     "Luke Causer <lcauser@oxfordquantumcircuits.com>"
 )
-release = version = "2.2.0"
+release = version = "2.2.1"
 add_module_names = False
 autoclass_content = "both"
 smv_remote_whitelist = None
diff --git a/pyproject.toml b/pyproject.toml
index 4bb746269..8d8f0ee71 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -2,7 +2,7 @@
 name = "qat-compiler"
 # This name has the -compiler suffix in order to use the poetry and twine tools to build and publish to PyPI
 # witout having to manually adjust the dist file names.
-version = "2.2.0"
+version = "2.2.1"
 description = "A low-level quantum compiler and runtime which facilitates executing quantum IRs."
 readme = "README.rst"
 documentation = "https://oqc-community.github.io/qat"
diff --git a/src/qat/purr/compiler/instructions.py b/src/qat/purr/compiler/instructions.py
index afc677ee2..bbefb4e80 100644
--- a/src/qat/purr/compiler/instructions.py
+++ b/src/qat/purr/compiler/instructions.py
@@ -400,7 +400,7 @@ class PostProcessing(QuantumInstruction):
     """
 
     def __init__(self, acquire: Acquire, process, axes=None, args=None):
-        super().__init__()
+        super().__init__(acquire)
         if axes is not None and not isinstance(axes, List):
             axes = [axes]
 
@@ -412,11 +412,10 @@ def __init__(self, acquire: Acquire, process, axes=None, args=None):
         self.axes: List[ProcessAxis] = axes or []
         self.output_variable = acquire.output_variable
         self.result_needed = False
-        self._acquire = acquire
 
     @property
     def acquire(self) -> Acquire:
-        return self._acquire
+        return self.quantum_targets[0]
 
     def __repr__(self):
         axis = ",".join([axi.value for axi in self.axes])
diff --git a/tests/qat/test_quantum_backend.py b/tests/qat/test_quantum_backend.py
index 6472b1146..70e284f4b 100644
--- a/tests/qat/test_quantum_backend.py
+++ b/tests/qat/test_quantum_backend.py
@@ -30,9 +30,13 @@
 from qat.purr.compiler.emitter import InstructionEmitter, QatFile
 from qat.purr.compiler.hardware_models import QuantumHardwareModel
 from qat.purr.compiler.instructions import (
+    Acquire,
     Delay,
+    DrivePulse,
+    MeasurePulse,
     PhaseReset,
     PhaseShift,
+    PostProcessing,
     SweepValue,
     Variable,
 )
@@ -677,3 +681,37 @@ def test_empty_channels_removed(self):
                     for p in positions
                 ]
             )
+
+    def test_create_duration_timeline_mapping(self):
+        """Test that instructions are correctly mapped to expected channels."""
+        hw = get_test_model()
+        qubit = hw.get_qubit(0)
+
+        builder = (
+            get_builder(hw).X(qubit, np.pi / 2.0).measure_mean_z(qubit).synchronize(qubit)
+        )
+        engine = get_test_execution_engine(hw)
+        qat_file = InstructionEmitter().emit(builder.instructions, hw)
+
+        position_map = engine.create_duration_timeline(qat_file.instructions)
+
+        drive_data = position_map[qubit.get_drive_channel()]
+        measure_data = position_map[qubit.get_measure_channel()]
+        acquire_data = position_map[qubit.get_acquire_channel()]
+
+        assert [type(pos.instruction) for pos in drive_data] == [
+            DrivePulse,
+            Delay,
+            PhaseReset,
+        ]
+        assert [type(pos.instruction) for pos in measure_data] == [
+            Delay,
+            MeasurePulse,
+            PhaseReset,
+        ]
+        assert [type(pos.instruction) for pos in acquire_data] == [
+            Delay,
+            Acquire,
+            PhaseReset,
+            *[PostProcessing] * 4,
+        ]