Spreadsheet : create a new table
Type a number in A1 (for example : 1)
Type the formula =A1 in A2 : (A2 shows : 1) [OK]
Delete A1 value (with 'DEL button') : (A2 shows : 0) [OK]
Cancel this last operation with CTRL+Z : (A1 shows 1) [OK] (A2 shows 0) [WRONG]
Hi..thanks for reporting. It's been reported before.
*** This bug has been marked as a duplicate of bug 80846 ***