Confused about marble and wonder bonus

[Artifex1]

It seems if you get marble in my borders and develop a quarry there that my wonder production time does not go down. Is this a bug?

I thought marble sped it up?

 

[RD-BH]

In city screen, hover over production.
You should see the bonus from marble listed.
If not listed and marble is in another city,
... verify uninterrupted trade routes to/from capitol.

 

[Johan de Witt]

[...]If not listed and marble is in another city[...]

If this happens (marble is between two cities and both can work the tile) the bonus goes to the city that actually has the tile as workable i.a. a can or is placed in it (so no arrows). You can swap this by clicking the tile from the city screen and then put that citizen in its original hex again.

Works the same with the bonus luxury from a Bazar.