Specular objects in general don't track very well. We're aware of the issue and working to improve the situation.
You can try to use the new extend map functionality to add new images of the same object in different lighting conditions to an existing map. This has the potential to improve tracking.
You can also use the exposure APIs in the WikitudeCamera (if you are using Unity), in case auto exposure is not working well for you.
We're working on a project that has to deal with specular objects in different light conditions, from very bright sun llight to darker conditions, in which we might also have to give an option for flash lights. But due to the very specular nature, certain objects don't localise and track in certain random conditions.
Is there a workaround or a way to control the camera in such a way that it can deal with multiple light intensities of the same object? We did think of taking multiple object scans and combining them using the studio application, but it seems to be a very tedious task.