Here are a few things to consider if your PowerPoint presentation is not displaying the correct font style for inserted equations:

1. Make sure you are using the correct font and font size for your equation.
2. Check your spelling and grammar to ensure the equation is the correct syntax.
3. Check to make sure your equation contains the necessary symbols, such as brackets, parentheses, and so on.
4. Ensure that all equation text is in the same font type and size.
5. If the inserted equation is a formula, make sure to place it in an appropriate box or frame.