While trying to adding supports one at a time is not smooth like V4. It will take several clicks to get the support to stick. I tried two models and it is the same thing.
I just added about 100 one at a time supports using the same 1mm and 45 degree settings that you were using, but it added the support on the first try every time. Is it possible this is related to the model you are using? If you try a different model does the same thing keep happening? If so, any chance you could attach a quick video?