MarkbookColumns.xlsc upload not working

I have uploaded the structure of markbook columns for 1st term of 2024-25 year cycle which worked well. I haven’t inserted any data into it. I then updated the same spreadsheet, which I’ve updated with 2nd Term outline for the same year using Update&Insert option. What happened it that the 1st term outline changed by itself to either just one column or none.
I am also unable to insert data in the 2nd term markbooks. 2nd term runs from Nov 2024 to Mar 2025. In the Date added column I entered today’s date but it didn’t help.
Please can you help?

I have just updated MarkbookEntry.xlsc. I removed some courses which I haven’t finished collecting data for. I thought these rows could not have been uploaded onto the system, since they were not complete. But when I uploaded the spreadsheet using Update&Insert option, it asked me to insert data for the exact rows I’ve deleted. I tried again using just Update then just insert option, but the same message occurred. Don’t know what happened and how to go around this?