It could be geometric or structural.
Geometric: when due to the shape of the structure (building corner, window box, inner wall connection to external wall, etc.), the heated, warming surface is smaller than the cooling surface (vice versa in summer).
Structural: when a material with a better thermal conductivity and lower thermal insulation capacity is installed in a given part of the building compared to the surrounding materials (e.g. concrete ring beam, lintels, reinforced concrete frames, etc.).
Knowledgebase