Workaround for now. When you hit edit, notice that the year drop-down is set to year instead of the actual year value. Make sure to change this every time. For the cost field, the text need to be removed entirely.
So if you have an item in collection with a purchase date set, and edit it to add a cost and do not fix the year, then the year will become 0000.
If you do this edit and do not remove the text from the cost field, the cost will show 0.00