Created attachment 87975 [details]
example demonstrating problem
Sorry for my English.
LibreOffice-184.108.40.206 has trouble that not exist in previous versions (at least LibreOffice-220.127.116.11).
Workbook of 2 sheets: "Sheet1" and "Sheet2". Cell "A1" of "Sheet1" contains value 42. Object's reference mySheet is messed after adding sheet. First MsgBox correctly reports value 42, but second don't.
Option VBASupport 1
Set mySheet = Sheets("Sheet1")
MsgBox("Before copy sheet: " + mySheet.Cells(1, 1).Value)
MsgBox("After copy sheet: " + mySheet.Cells(1, 1).Value)
Code like above is from file generated by another program beyond our control.
Attachment contains sample file. Try to run macro bug_demo.ods -> Standard -> Module1 -> Main.
*** This bug has been marked as a duplicate of bug 70079 ***