Cells randomly being highlighted when clicking a cell

Not sure what version of Excel it is but when I click a cell it will randomly highlight a bunch of cells above the cell im clicking (e.g. I click cell A25 and it highlight A25 up to A3 or something). I have changed mouse, mouse pad and the issue is less but still there. This is at work, multiple computers use the same sheet, the issue is only present on 1 computer, the sheet is shared. Any ideas or help.