Date Field value DISAPPEARS

My application is tracking domain names. There is an 'expire_date' field and there is a rating field called 'NFJ_Tier' (Multi-Select)

I display the data in a 'spreadsheet' view (called SCORE) so that I can quickly make changes to NFJ_Tier for many records at once.

Even though 'expire_date' IS NOT used in the SCORE view at all... When I "save" changes (scores on NFJ_Tier) every corresponding 'expire_date' value changes as well to NOTHING.

It CLEARS THE expire_date field ENTIRELY!

This is NOT GOOD. NOT GOOD AT ALL! What the HELL is going on???????