Yes the layer 11 change is pretty odd. And it does that for the border also. And indeed removing the color change also has no effect. I’ve not seen that before.
I wonder if it’s some “issue” with the model, or how Studio is tessellating (converting) the STEP solid into a mesh. Have you tried exporting from Fusion in a mesh format (“Save as Mesh” not File → Export)? I don’t know why it would do that if the text/border don’t penetrate the base, but it’s Studio so anything is possible… 
Personally in Fusion I’d make the red parts be separate bodies. Then r-click the parent component, and Save as Mesh (STL, to avoid further Studio shenanigans with color later). Import the STL into Studio, r-click and Split → to parts. Then assign filament color directly to the parts.
Fusion will want to make separate bodies for each letter of the text… which works but can be annoying to manage. One trick I learned is to place all the text onto a very thin “base” plate, thinner than any layer height you may use, like 0.01mm. Then extrude the text and join to that base… this way there’s just one body for all the text, but the thin base plate is ignored in the slicer because it is too thin to print. I posted an example of that once, here: Make flush prints - #23 by MaxThreeD
-Max