microsoft.public.it.office.excel

In an complex vba excel application after the run of a macro any
attempt to write data fires a strange phenomenon; multiple areas of
various worksheets overlap each other on the screen. To stop this
behavour I must close the file saving the edits and reopen it. I
observe this, running the file in Excel 2003 but not in 2000, 2007,
2010. Is it a bug of Excel 2003 or a partially corrupted file. In the
last case why only in 2003 excel version?
Thanks per any suggestion