there is a cell in which information is around 3000 bytes of text.
I replaced some parts of the text data twice and saved it as another file.
However, I have found around 30% of the last part of the information inside cell has disappeared. exactly not stored.
This cord is working well for other data.
The strange thing is that I can find just the correct information during debugging at every step.

logically the cord is like below.

info = sheet[row, "header name"]
info = info.replace(old1, new1)
if ---:
info = info.replace(old2, new2)
sheet[row, "header name"] = info
sheet.save_as(filename)

For the other data, it works perfectly.
But just at the long text cell, some parts of information look not stored.
What can be the cause?