Blender transparent model Import and wierd line appears

I'm new to both unity and blender
I tried to make a jar half filled with sugar(I think)
in blender it looked like this
not perfect but this is the best I can do right now
then import into Unity

Blender transparent model Import and wierd line appears
a line(face?) appears and kind of disable the mask looking through it
anyone tell me how to solve this?

also, the sugar part look like jelly...