low coolant level

Hi. Bought BMW 525dx, 2014, 150k kilometers. Found out under the hood that level of coolant is MIN, not between min and max as should. There no weird noises while driving, no warnings from bmw about low level, no smells, no errors, oil level in engine ideal, no smudges, everything is dry. I am planning to change all oils and liquids, but still i am interesting why it on min level and is it normal or not for this car. And how can i resolve it?

I have checked on cold car this morning.

Thank you!