Conditional check for null equality works in normal flow but fails unit test with internal server error

[Reisclef]

Azure Logic Apps (Standard) 5.961.19
Microsoft.Azure.Workflows.WebJobs.Tests.Extension 1.0.3

Describe the Bug

When unit testing a workflow containing a null equality check for an object variable, the test will fail stating an internal server error with no other details.

Plan Type

Local

Steps to Reproduce the Bug or Issue

1. Create an HTTP workflow with an object variable, and a conditional check for the variable to equal null
2. Run workflow and observe success
3. Create a basic unit test to check for success
4. Observe that the unit test fails

Workflow JSON

{
    "definition": {
        "$schema": "https://schema.management.azure.com/providers/Microsoft.Logic/schemas/2016-06-01/workflowdefinition.json#",
        "contentVersion": "1.0.0.0",
        "actions": {
            "Initialize_variables": {
                "type": "InitializeVariable",
                "inputs": {
                    "variables": [
                        {
                            "name": "PossiblyNullObject",
                            "type": "object"
                        }
                    ]
                },
                "runAfter": {}
            },
            "test_Resp": {
                "type": "Response",
                "kind": "Http",
                "inputs": {
                    "statusCode": 200
                },
                "runAfter": {
                    "Condition": [
                        "SUCCEEDED"
                    ]
                },
                "operationOptions": "Asynchronous"
            },
            "Condition": {
                "type": "If",
                "expression": {
                    "and": [
                        {
                            "equals": [
                                "@variables('PossiblyNullObject')",
                                "@null"
                            ]
                        }
                    ]
                },
                "actions": {},
                "else": {
                    "actions": {}
                },
                "runAfter": {
                    "Initialize_variables": [
                        "SUCCEEDED"
                    ]
                }
            }
        },
        "outputs": {},
        "triggers": {
            "test_req": {
                "type": "Request",
                "kind": "Http",
                "inputs": {
                    "method": "GET",
                    "schema": {}
                }
            }
        }
    },
    "kind": "Stateful"
}

Screenshots or Videos

No response

Additional context

[TestMethod]
public async Task Test_PossiblyNullObjectCondition_WorkflowSucceeds()
{
    var triggerMock = new TriggerMock(status: TestWorkflowStatus.Succeeded, name: "test_req", outputs: (MockOutput)null);

    var testRun = await this.TestExecutor.Create()
                .RunWorkflowAsync(testMock: new TestMockDefinition(
                    triggerMock: triggerMock,
                    actionMocks: new Dictionary<string, ActionMock>()))
                .ConfigureAwait(false);

    Assert.IsNotNull(testRun);
    Assert.AreEqual(TestWorkflowStatus.Succeeded, testRun.Status);
}