When importing a PowerPoint into Storyline 3, the slides show as widescreen on the "Insert Slides" screen, however after the slides are inserted to the project the slides are now in 4:3. Changing the scene back to 16:9 causes the images and text to become distorted.
There doesn't seem to be any consistency to this happening. Sometimes it will occur with the same lessons, sometimes it own. Closing and opening Storyline will sometimes correct it, but not guaranteed.