In addition to the obvious overuse of buttermilk, the popular recipe I found online has many problems. The author gets it right when calling for self-rising flour, which is flour containing salt and a leavening agent (aka baking powder), but why would the copycat Bojangles biscuit recipe be designed to use self-rising flour and then add additional leaving? Well, it probably wouldn’t. Biscuits are job number 1 for self-rising flour, and the leavening in there is measured for that use, so there’s no need to add more. If you were planning to add your own leavening, you’d probably start with all-purpose flour, which has no leavening in it. And let's just be clear: baking powder tastes gross, so we want to add as little as possible, not more than necessary.