ᐅ Thermal bridge? Concrete ceiling versus surface temperature.

Good day.
I am interested in the topic of thermal bridges (or cold bridges—are they the same?).
I measured the surface temperature of the walls and ceilings in my apartment (KfW 70 standard, Poroton blocks, 4 years old).
I noticed that one ceiling in the home office shows different surface temperatures.
This ceiling is located on the upper floor (first floor), and above it, in the attic floor, there is 50% living space (heated) and 50% unheated area (roof terrace, half covered).
The surface temperature of the ceiling is about 21°C (70°F) in the heated area.
In the unheated area, where the roof terrace is above, the ceiling temperature is only about 17°C (63°F).
Measurements were taken at about 0°C (32°F) outside temperature, with the apartment heated.
Also, the exterior walls beneath the roof terrace are colder compared to the exterior walls beneath heated rooms of adjacent apartments.

My question:
Do these temperature differences indicate the presence of thermal bridges, and could they cause long-term problems such as mold?
PS: Of course, an expert could clarify this with various measurement methods.
But first, I would like to get some tips and advice here.
Or is it normal for a ceiling located beneath a roof terrace (half covered) to be naturally colder than a ceiling beneath a heated room? That would be understandable.
However, the transition of the ceiling temperature from the warmer to about 4 degrees cooler near the exterior wall concerns me a little and interests me.

Thank you very much.