Why does my axis title keep returning to horizontal (instead of staying vertical)?

everytime I reopen my spreadsheet (after saving it with 4 graphs with a vertical (90) degree axis title, and varying font sizes for axis variables, and then when I reopen all the above goes back to default font size and the worst part is that the asix title (of the y-axis_ goes to horizontal,? this weird, because it hasn’t happened before, please help
thanks
joy

Please note the key detail required for questions. To help us help you please edit the question accordingly. Thanks.