I don't think the car should disable the smart portion of cruise control on it's own. That could just plow you into the car ahead unless you have been properly warned. If the radar is disabled, the AEB isn't going to work either.
Personally, I hate smart cruise control. I might like it if I frequently drove in heavy multilane traffic and wanted to zone out in one lane, but I don't do either. I've tried it a few times, but keep having it brake unexpectedly when a car ahead has almost completed a right turn and there is no way to hit it. Regular CC doesn't miss a heartbeat under those conditions. I don't even get a proximity pre-AEB warning.
Right hand side of steering wheel, bottom left button is to adjust the smart cruise distance a car length at a time. But if you hold it for three seconds, you will have an option on the LCD behind the steering wheel to change it from smart to regular. This is supposed to stay "sticky" for next time the CC is engaged after turning car off. However there seems to be a bug as mine does not. I don't even get the screen with the choice when depressing the distance button, but it does toggle from one mode to another (doesn't say which one). So every time I use the CC, I forget to toggle, engage, disengage, depress for three seconds, and engage again.
I'd be interested to know if that is everyone else's experience too (I realize most may just leave it in "smart"). But if folks could play with it, that info will help when I bring this to the dealer's attention.
2018 Kia LX HEV Metal Stream with Advanced Tech