The routing programme appears to understand 'surface=paving_stones:30' as unpaved. Cycleways with this tag come up in routing advice as 'unpaved trail'. This is incorrect.
'surface=paving_stones:30' is often used in the Netherlands to indicate paving stones of 30 x 30 cm, so the path is paved. Cycleways with this pavement are often not the best quality, but you can't say they're unpaved.