I noticed a problem in NEMS visualization.
Although there is zero rain on map, there is a rain symbol and a rain accumulation in the meteogram
the same for the next time steps
... I investigated further (with data from meteoblue) and I think you use
their "old maps", but your meteogram uses "new map" data
As you can see, for same time, "old maps" show no rain over NorthWest Greece
but "new maps" show rainy conditions for the same area.