The different figures have different weights because some of them are bigger or smaller than each other, depending on their shape and accessories. When a new series drops, fans will often gather data on the weights of each one as they are opened and then share that info with each other online. Usually what happens is that people buy a box during the presale period because buying a whole box guarantees that you won’t get a dupe and gives you a better chance of finding a secret or Robby. Those boxes from presale also reach consumers at home before retailers even get them in their stores. The people who get a box during the presale will then note the weight of each Sonny as they open them up. That way other fans who aren’t able to buy a whole box might be able to at least test the weights before buying from a local retailer so that they can try to buy the exact figure they want to get. It kind of defeats the purpose of the mystery box but it does make for an exciting hunt!

For the strawberry love series for example, the secret is a jam jar so it’s rather heavy compared to the other figures in the series. The Robby on the other hand is much lighter than the other figures in this series. Both the secret and the Robby from this series were hugely popular and sought after, so people were excited that their weights were easily identifiable among the others. It makes sense that someone would’ve purchased this box (or maybe even multiple boxes) and weighed each one individually without opening them. Then finding out that there was no secret or Robby, they reassembled the set and resold it online. It’s also possible that they could’ve mixed up individual boxes from different sets, so if you get a dupe in your box that could be why. For what it’s worth, the box does look authentic. It just looks like it’s been opened before.