fix

Prevent user from selecting use unreliable deltas when SwitchTransformSpaceWhenParented is enabled (and vice versa).
Adding check during runtime to also notify the user that this combination does not work (i.e. missed updates can result in a missed transform update when parenting changes).

Author: NoelStephensUnity

com.unity.netcode.gameobjects/Editor/NetworkTransformEditor.cs

@@ -184,13 +184,45 @@ private void DisplayNetworkTransformProperties()
             EditorGUILayout.Space();
             EditorGUILayout.LabelField("Delivery", EditorStyles.boldLabel);
             EditorGUILayout.PropertyField(m_TickSyncChildren);
-            EditorGUILayout.PropertyField(m_UseUnreliableDeltas);
+            // If both are set from a previous configuration, then SwitchTransformSpaceWhenParented takes
+            // precedence. 
+            if (networkTransform.UseUnreliableDeltas && networkTransform.SwitchTransformSpaceWhenParented)
+            {
+                networkTransform.UseUnreliableDeltas = false;
+            }
+            GUI.enabled = !networkTransform.SwitchTransformSpaceWhenParented;
+            if (networkTransform.SwitchTransformSpaceWhenParented)
+            {
+                EditorGUILayout.BeginHorizontal();
+                EditorGUILayout.PropertyField(m_UseUnreliableDeltas);
+                EditorGUILayout.LabelField($"Cannot use with {nameof(NetworkTransform.SwitchTransformSpaceWhenParented)}.");
+                EditorGUILayout.EndHorizontal();
+            }
+            else
+            {
+                EditorGUILayout.PropertyField(m_UseUnreliableDeltas);
+            }
+            GUI.enabled = true;
+
             EditorGUILayout.Space();
             EditorGUILayout.LabelField("Configurations", EditorStyles.boldLabel);
-            EditorGUILayout.PropertyField(m_SwitchTransformSpaceWhenParented);
+            GUI.enabled = !networkTransform.UseUnreliableDeltas;
+            if (networkTransform.UseUnreliableDeltas)
+            {
+                EditorGUILayout.BeginHorizontal();
+                EditorGUILayout.PropertyField(m_SwitchTransformSpaceWhenParented);
+                EditorGUILayout.LabelField($"Cannot use with {nameof(NetworkTransform.UseUnreliableDeltas)}.");
+                EditorGUILayout.EndHorizontal();
+            }
+            else
+            {
+                EditorGUILayout.PropertyField(m_SwitchTransformSpaceWhenParented);
+            }
+            GUI.enabled = true;
             if (m_SwitchTransformSpaceWhenParented.boolValue)
             {
                 m_TickSyncChildren.boolValue = true;
+                networkTransform.UseUnreliableDeltas = false;
             }
             else
             {

com.unity.netcode.gameobjects/Runtime/Components/NetworkTransform.cs

@@ -1958,6 +1958,16 @@ private void TryCommitTransform(bool synchronize = false, bool settingState = fa
                 m_UseRigidbodyForMotion = m_NetworkRigidbodyInternal.UseRigidBodyForMotion;
             }
 #endif
+            // Authority check to assure that UseUnreliableDeltas is not set during runtime while using SwitchTransformSpaceWhenParented.
+            if (SwitchTransformSpaceWhenParented && UseUnreliableDeltas && !m_LocalAuthoritativeNetworkState.FlagStates.UnreliableFrameSync)
+            {
+                if (m_CachedNetworkManager.LogLevel <= LogLevel.Normal)
+                {
+                    Debug.LogWarning($"Reverting {nameof(UseUnreliableDeltas)} back to fals as it cannot be enable while {nameof(SwitchTransformSpaceWhenParented)} is enabled!");
+                }
+                UseUnreliableDeltas = false;
+            }
+
             // If the transform has deltas (returns dirty) or if an explicitly set state is pending
             if (m_LocalAuthoritativeNetworkState.ExplicitSet || CheckForStateChange(ref m_LocalAuthoritativeNetworkState, synchronize, forceState: settingState))
             {