conditional formats lost

[rbtrader]

I have a spreadsheet that uses conditional formats. The data in the
spreadsheet is live data from my broker using DDE links. Most every time I
open the spreadsheet all of the conditional formats are gone. I verify this
by using the menu item - manage conditional formats. There are no formats in
the list. To correct the situation, I close the sheet and open it again.
Usually when I open it the 2nd or 3rd time the conditional formats are there.
Why does this happen?