after merging and unmerging cells, there at least 2 errors we saw.
First, we cannot input any text into some cells of those merged cells.
Second, some cells lost its background color
1. displaying attached file in Spreadsheet
2. select 9 cells with background
3. select "merge across"
4. select "merge cells"
5. select "Unmerge cells"
all cells revert back to original status.
As description said, there are 2 obvious problem.
Input area of some cells become very narrow and entering text cannot appear in the cell. The background of 4 cells disappear.