I noticed from the sippy cup thread that a good number of us like the Zolibot straw cups. Do you have a problem with them leaking? Liquid seems to come up from the straw sometimes. I called their customer service and they gave me straw replacements which helped for maybe a month but now they are leaking again. Anyone have any tips for solving the leaks or do I have to buy brand new ones? Maybe I shouldn't put them in the dishwasher? Do you all hand wash yours?