When saving document all tabs were deleted except the main tab. 3/4 of the data on that tab was deleted as well. original document in .csv format - saved back to that format.
Version: 5.4.1.2 (x64)
Build ID: ea7cb86e6eeb2bf3a5af73a8f7777ac570321527
CPU threads: 8; OS: Windows 6.19; UI render: default;
Locale: en-US (en_US); Calc: group
CSV is a plain text table data; and it is by design unable to hold more than one sheet. If you save multiple-sheet spreadsheet to it, it will loose all but first - that’s normal.
Also it’s unable to save formatting; graphical data (including charts); and many more. Use ODS to have full support of all LibreOffice Calc features.
A bit of correction - saving multiple-sheet spreadsheet to CSV will save currently active sheet, not the first one and will generate warning
Warning saving the document -filename-:
Only the active sheet was saved.