New User - Colouring a Dice

Hi, I am new to 3d printers, Bambu Labs, and Bambu Studio. I’ve created a 3D Dice in Fusion 360, with lettering on the sides. In Bambu Studio, I have attempted to paint the face of the indented lettering, but have noticed when slicing, that the colour of the indented letters bleed to the centre of the dice, rather than just being a face colouring.

Images to explain below.

Is there a way to adjust the settings in the slicer to only paint at surface level? Is the problem I notice this is the case with the “top” face, but only causes problems down the sides.

Is there a way around this?