Failure in cascading deletion

[CBenghi]

Hello @martin1cerny,

As I'm working on restoring al CI/CD processes I had to set the ignore flag on a failing test at the following line:

XbimCobieExpress/Tests/CobieTests.cs

Lines 97 to 101 in 1de3c7f

	[Ignore("@martin1cerny, this is known to fail, but looks like a bug. Could you have a look?")]
	public void Deletion()
	{
	var model = CreateTestModel();
	using (model.BeginTransaction("Deletion"))

Is it an easy one for you to fix?