Ha funny, there's absolutely no feedback elements designed to reduce the gain with frequency, either on the current limit of voltage limit - this will cause oscillation where the knee point is reached, i.e. crossover between the two states - this is not a design created (or tested) by a power electronics engineer (i.e. with a BE).
I note it is vaguely stable at no load, but the Vo ave is way different, needs an hour or so of looking at and then suggesting values in the two loops to try...