Your CSV file is not valid because your descriptions contain LF (line feed) character without being properly escaped.
It’s actually quite common issue but it is not Manager fault. For this reason, in near future it will not be possible to import CSV files at all. Instead you will need to copy & paste your transactions from some spreadsheet program which will make this issue go away. Spreadsheet programs will correctly escape new line characters during copy/paste operation so Manager receives valid data.
For the time being, when you export your spreadsheet into CSV format, spreadsheet program should do the right thing and properly escape new line characters within cells.