Show me the ultrarunner who has not had issues. I don't think that person exists. It's too much of a painful lonely sport attract people like a giant party. It's not just finish lines and after parties. The vast majority of it is out on the road and trails, alone, putting in the work so that maybe hopefully for that one short moment everything will culminate in a personal record and I will have achieved something I doubted was possible year ago.
Case in point, I hit the glycogen wall hard this morning on my long run, very poor carboloading after my run yesterday.