A Google spokesperson explains:
Promoted pins in navigation are not new – they let people see relevant ads for businesses like gas stations, restaurants, and stores along their route. To avoid driver distraction, these ads do not pop up, expand only if they’re tapped on, and disappear quickly after a short time.
There is no popup whatsoever during navigation. The alleged popup screen is actually what appears when you yourself click a pin (whether normal or sponsored). Nothing ever pops up by itself.
The article was corrected, maybe you read it before that happened.