This is occurring because the font style of the bullet point is not defined properly in the original PowerPoint file. Please see the image of the Font Style Box.
The Font box does not have anything in it. Apply the (normal text) font style for the bullets within the text box. You should do this for each text box with bullet points that are affected.
Below is a step-by-step of how to go through and change the bullets:
- Highlight and right-click the text that includes the bullets points
- Scroll down to Bullets and hover over the arrow
- Click on Bullets and Numbering
- Ensure that the "-" style (correct bullet style) is selected
- Click on Customize
- In the Font section, type (normal text)
- Click OK
- Click OK again
- Click Save
This will need to be repeated for each of the text boxes containing affected bullet points.