Same issue on my one of two Lucid Lynx(10.04) installations; Every two weeks notifying doesn't work => only every day.
I solved it with reinstalling all installed packages with name *packagekit* (easy with synaptic), after that I went to the kpackagekit settings tab again, selected "every day"-checking , then back to "every 2 weeks"-checking, "close"-Button.
Afterwoods I pressed the apply-button and closed kpackagekit.
=> Restart and notifying is working again.
Same issue on my one of two Lucid Lynx(10.04) installations; Every two weeks notifying doesn't work => only every day.
I solved it with reinstalling all installed packages with name *packagekit* (easy with synaptic), after that I went to the kpackagekit settings tab again, selected "every day"-checking , then back to "every 2 weeks"-checking, "close"-Button.
Afterwoods I pressed the apply-button and closed kpackagekit.
=> Restart and notifying is working again.
Best regards, Bernhard