I think the fonts displaying in the Font choices are displaying by alphabetic order, not based on what you have currently chosen for your chart... 

1. create a chart

2. open the chart options

3. notice the font listed in Format ( I have Arial bold )

4. click on the dropdown to display the font list that shows what the fonts look like.

5. notice that the font displayed is not the one you currently have selected. ( Agency FB is shown, not Arial from the preceding step )

6. click the Cancel button.

7. the font which displayed in the dropdown ( Agency FB) is now your selected font, even though you clicked Cancel on the font dropdown which should have put you back at your Arial bold from step 3.

see attached GIF animation