Problems with editing symbol

Hi Creatives! I'm experiencing some odd problem when editing symbol. Everything works fine apart from one thing.

 I've got drawings of fruits and veggies (engraved style) and when I try to make the outline thicker it comes to one point when it's being stopped/cut as if theres a frame and I can't go beyond it. There is a frame indeed but I made it bigger (keeping the drawing same size) and it didn't help. Any ideas?