Thank you for reporting a bug to Unity.

After investigating this bug, we found that the infinite hang is caused by the code in CutListComponent :

public void Recalculate()
{
CutListGenerator.partMax = partMax;
cutList = CutListGenerator.GetCutList(.....); //Edit serial value
}

private void OnValidate() //Called after serialization
{
update = false;
Recalculate();
}

In Recalculate, a new CutList array is assigned to cutList. This will trigger another serialization and call to OnValidate, which will assign a new array and so on.
Your "update = false;" line in the OnValidate method suggest that you are missing a "if(!update) return;" that would prevent this infinite loop.

Also, concerning the warning : Serialization depth limit 10 exceeded at 'SheetCutList.cuts'.

It can be resolved by adding a [NonSerialized] attribute in SheetCut l.15 :
[NonSerialized]
private SheetCutList allCuts;

To prevent a loss of context in the editor, we might try to serialize a private field so that we can restore its value after a domain reload.
In such cases, we test for recursive serialization, hence the warning.

Thank you again for taking the time to report this issue, and please let us know if there is anything else that changes the context or severity of this issue.