If you select these dropouts, by default BikeCAD will suggest different values for Cx vs C2x and Cy vs C2y. These are the dimensions controlling the ends of the chainstays relative to the rear axle. Cx is the drive side and C2x is the non-drive side.

You don't actually have to select asymmetric stays. If it is only C2x and C2y that will be different when you compare the drive side chainstay and the non-drive side chainstay, you can leave the chainstays set to symmetric. In this case, technically the chainstays are asymmetric, but because that asymmetry is defined in the Rear dropouts dialog box, and all the specifications given in the chainstay dialog box are applied the same to both stays, BikeCAD is fine calling these stays symmetric in the context of the chainstays dialog box.

However, if you would also like to define some differences in curvature or tube shape between the drive side and non-drive side stays, it is also fine to click the aymmetric checkbox in the chain stays dialog box.

The only problem here is if you toggle back and forth between asymmetric and symmetric stays. When you go from asymmetric to symmetric stays, BikeCAD will set C2x equal to Cx and C2y equal to Cy. In your example, I assume that C2x was initially a different value than Cx. However, because at some point, the stays may have been toggled from asymmetric to symmetric we now see C2x equal to Cx.

To resolve this, simply select a different dropout and then go back and select the DR1102 dropout again. This will reset the values for Cx, C2x etc. Be aware that you can also modify the values for Cx and C2x to suit your own preferences. The DR1102 dropouts are a plate style dropout and you do have some flexibility in terms of how much the ends of the stays overlap the dropouts.

Let me know if this behaviour does not explain the situation you are seeing in your example.