Exposed date filter can cause fapi errors

I'm not entirely sure if this is replicable, but in my case I created a view and exposed a date filter. I then saw the checkbox to "remember" the last setting used. I enabled it and decided I didn't need it so disabled it... This didn't wipe the data from $_SESSION and whenever I went back to the page, the fapi element always had #value set which overrode the #default_value. It also caused errors in that it was trying to select values from the year and month drop downs which didn't appear to exist causing "please contact your admin" errors.

Ironically, after spending about 24 hours debugging this, I solved it by logging out and in again thus wiping my $_SESSION clean...