There are multiple solutions though but you can choose what suits you, I recently bought a YBR 125g and I do not have this issue,
1: Get your seat replaced in warranty.
2: Go to the warranty center and tell them about your issue, they will add a cotton sheet on to your seat with a new cover, that will solve your issue, I have seen this happen on another customer's YBR when i went to the warranty center to get an issue fixed with my bike.
Good Luck and stay positive.