The value 9, which was in cell B2 before merging, is lost as the unmerging process discards the content of the adjacent cells.
The contents of cell A2 (value 8) remain after cell A2 and B2 are combined, whereas cell B2's contents (value 9) are eliminated. The value from the upper-left cell (in this case, cell A2) is now present in the merged cell.
Upon unmerging the cells, the merged cell is split back into its original individual cells (A2 and B2). The value 8, originally in cell A2, remains in cell A2.
However, the value 9, which was in cell B2 before merging, is lost as the unmerging process discards the content of the adjacent cells.