What precaution must be taken when finishing and holding Allemande sause?

When finishing and holding Allemande sauce, it's crucial to avoid boiling it after adding the egg yolks, as this can cause the sauce to curdle. Additionally, keep the sauce warm in a bain-marie or over low heat to maintain its consistency and prevent it from thickening too much or forming a skin. Stirring occasionally will also help to keep it smooth and prevent separation.