Happened to me before. 300 energy no shards. I've also been lucky enough to experience the other way, something like 7 shards on a 10 sim, but that's only happened once while the former maybe 2 or 3 times.
I like to sim in 3's, just mentally I feel like I get better drop rates, usually 1 per 3 sims which falls in line with their information. I might try to study my drops for a few weeks to see the results but that's a lot of work for not much benefit.
Didn't they just pass a new law in China a couple months ago so all mobile gaming companies have to give out the exact chance for any RNG aspect of their game? I would love to know if anyone has found this information and could give us a link or something to it, hopefully with a translation if it's in Chinese. That would not only stop people from asking these questions because they got super shafted on gear one time(I'd be mad too if roughly 300 energy turned into nothing), but then we would all know the chance for things to drop, which is really what we've always wanted, right?
And of course it would be much more reputable information since it's a law, rather than someone getting to decide what information to tell the public and what to leave out.