Steps to reproduce:
1. Create new Unity project using High Definition 3D Template
2. Press AI button on the top Editor toolbar and press “Agree and install Unity AI” button
3. Wait for package to finish installing and observe the Console

Actual results: Errors are thrown in the Console window

Expected results: No errors thrown in the Console window

Reproducible with versions: 1.5.0-pre.1 (6000.3.4f1, 6000.4.0b4, 6000.5.0a4)
Can’t test with versions: 6000.0.65f1 (No AI packages)

Tested on (OS): macOS Silicon Tahoe 26.2 (M1), Windows 11

Notes:

•  On 6000.3 stream, it's 50/50 chance errors will be thrown, sometimes errors appear, sometimes - not

Errors:
{code:java}
Lifecycle ERROR : Failed to setup LifecycleManagement and enter code reload scopes (pre deserialization) due to exception System.NullReferenceException: Object reference not set to an instance of an object
at Unity.Scripting.LifecycleManagement.OrderedAssemblyList.TopologicalSortRecursive (Unity.Scripting.LifecycleManagement.OrderedAssemblyList+SortNode[] sortNodes, System.Boolean[] visitedNodes, System.Int32 index, System.Reflection.Assembly[]& sortedNodes, System.Int32& sortedCount) [0x0002d] in /Users/bokken/build/output/unity/unity/External/ScriptingCore/Unity.Scripting/LifecycleManagement/OrderedAssemblyList.cs:139
at Unity.Scripting.LifecycleManagement.OrderedAssemblyList.TopologicalSort (System.Reflection.Assembly[]& assemblies) [0x00142] in /Users/bokken/build/output/unity/unity/External/ScriptingCore/Unity.Scripting/LifecycleManagement/OrderedAssemblyList.cs:127
at Unity.Scripting.LifecycleManagement.OrderedAssemblyList.Populate (System.Collections.Generic.IEnumerable`1[T] assemblies) [0x0001a] in /Users/bokken/build/output/unity/unity/External/ScriptingCore/Unity.Scripting/LifecycleManagement/OrderedAssemblyList.cs:49
at Unity.Scripting.LifecycleManagement.OrderedAssemblyList..ctor (System.Collections.Generic.IEnumerable`1[T] assemblies) [0x00011] in /Users/bokken/build/output/unity/unity/External/
ScriptingCore/Unity.Scripting/LifecycleManagement/OrderedAssemblyList.cs:32
{code}
{code:java}
NullReferenceException: Object reference not set to an instance of an object
Unity.Scripting.LifecycleManagement.OrderedAssemblyList.TopologicalSortRecursive (Unity.Scripting.LifecycleManagement.OrderedAssemblyList+SortNode[] sortNodes, System.Boolean[] visitedNodes, System.Int32 index, System.Reflection.Assembly[]& sortedNodes, System.Int32& sortedCount) (at /Users/bokken/build/output/unity/unity/External/ScriptingCore/Unity.Scripting/LifecycleManagement/OrderedAssemblyList.cs:139)
Unity.Scripting.LifecycleManagement.OrderedAssemblyList.TopologicalSort (System.Reflection.Assembly[]& assemblies) (at /Users/bokken/build/output/unity/unity/External/ScriptingCore/Unity.Scripting/LifecycleManagement/OrderedAssemblyList.cs:127)
Unity.Scripting.LifecycleManagement.OrderedAssemblyList.Populate (System.Collections.Generic.IEnumerable`1[T] assemblies) (at /Users/bokken/build/output/unity/unity/External/ScriptingCore/Unity.Scripting/LifecycleManagement/OrderedAssemblyList.cs:49)
Unity.Scripting.LifecycleManagement.OrderedAssemblyList..ctor (System.Collections.Generic.IEnumerable`1[T] assemblies) (at /Users/bokken/build/output/unity/unity/External/ScriptingCore/Unity.Scripting/LifecycleManagement/OrderedAssemblyList.cs:32)
{code}