Python - Trouble writing a number with a comma in Excel?

Question

Python

I use BeautifulSoup to parse data from a website. For writing to excel - openpyxl.
Numbers with a dot (for example, 39.40) writes. If fractional (39.40), then only 39 is inserted into the cell.
What is the reason?

PS: if you specify the float data type when extracting and writing, then the record will be like this: 39.00. Cuts off everything after the comma.