Center not visible for Guides
When e.g. a Rectangle is made a Guide, while the Center Attribute is active, the Center dissappeares. Very inconvenient, since the center is a very helpful position for a Guide.

the centre point is visible when you select the rectangular guide.
Please accept my sincere apology for the inconvenience. Please get in touch with us at any of the other support channels – https://helpx.adobe.com/support.html . Since this is not a generic issue that we can reproduce at our end, we will need someone to look into your machine to figure out what is going on here.