If the reservoir, which holds the unfiltered water, is not correctly aligned the lid won't lie "flat".
The two ends of the reservoir are slightly different shapes. If inserted into the pitcher the wrong way round, it will prevent the lid from sitting properly.
To fix this issue:
  • Remove the lid and reservoir
  • Find the end of the reservoir that has a small tab
  • Line the tab up with the handle and the reservoir will easily drop back into place
  • Attach the lid