Worth mentioning, this bug happens for me consistently when doing an Apollo-style 2 stage lander like PicoSpace had. I think when taking off while staging at the same time can cause the issue, as I found if I took off briefly with the descent stage (just to get off the ground) and then staged to start flying with the ascent stage, the conics showed as intended. If I just took off directly with the ascent stage (as PicoSpace did in the video) then it broke.