I have a refurbished 10CPM bought and installed in October. I realized I have a leak somewhere because my glass is turning black after a day's use (currently using MWP blend). I've tweaked the lid latch and it closes nice and tight but the front left corner is clearly not snug. The gasket is in good condition and the hopper seals nicely everywhere else. In that front corner you can easily slide a dollar bill in and out without any resistance and if you stand back there is a noticeable gap. Is it possible that the lid is warped and just won't sit right? I am going to call customer service tomorrow but thought I'd check in here first for any suggestions. Thank you in advance for your help.