Hello,
Not sure if I see it correctly, it may be different on your browser but I think that Radio 1 and Radio 2 are unchecked in both screenshots you provided. "Inherited" is also unchecked which means that you should be able to modify this configuration.
Here is how an enabled radio should look like. I am using MSM 6.6.40 and Google Chrome.

After setting the checkmark you should click on save. The AP will become unsynchronized, you have to synchronize it in order to apply the changes.
Or you can set the checkmark before Inherited, click save and check if the checkmarks before RAdio 1 and Radio 2 were set. Enabling Inheritance means that you apply the AP group settings to this AP.
Another option is to check what type of AP groups you have on the MSM760 and if the APs are in the correct group at the moment. You can change the group of an AP by selecting the AP in the Network Tree (left side of the GUI) then opening top side menu Device Management and selecting a different AP group from the drop down menu. Drag and Drop within the Network Tree should also be possible.