Usually after all day at Cyro I've been opening all received boxes with one char. And usually received 3-5 Uncracked Geodes from 15-20 rewards. Today got nothing, how about you, guys?
You are guaranteed to get one, from the first one you open in a 24 hour period. After that its a random chance to get another one. Its more likely that your luck is just bad today (or the gods of RNG demand a sacrifice).