I would have to look at the Lee profile, actually measure it up, to see if I could see what the design flaws are. I'm convinced that is the problem. Something about them lets them wobble before they leave the gun, or perhaps the ogive form, relitive to meplat size.
I have definately had bullets wonder off coarse, in deer, twice, but they were not LBT designs. that we sell. Furthermore, I have not heard one customer complaint, or report of such happening in the 32 years I've been selling my designs. God only knows how many animals have been punched through in all those years, with no problems. So, I definately recommend that you get an LBT design, and would recommend an LFN for your 475. 400 grains is very popular as is 385 gr where people want to keep recoil down. I don't recommend weights over 440 gr, but do make them on request.