H3 seems to normally shrink

[HappyTableTennis]

My H3 which is unboosted, shrieked where the top edges wouldn’t fit, I purposely left 2mm when cutting it to try and prevent and seems it doesn’t work, is this normal to H3?

 

[TensorBackhand]

My H3 which is unboosted, shrieked where the top edges wouldn’t fit, I purposely left 2mm when cutting it to try and prevent and seems it doesn’t work, is this normal to H3?

I've never heard this before. Never had this issue with Chinese rubbers.