Parental controls "Medium" doesn't enable DuckDuckGo SafeSearch

Hello, parental controls “Medium” safety level is described this way: “Includes everything below in Bajo and enables SafeSearch, an automated filter that helps keep pornography and other offensive content out of Google, YouTube, Bing, and DuckDuckGo search results.”

In my testing, the SafeSearch is indeed enabled for Google, YouTube, and Bing.  But DuckDuckGo continues to allow unrestricted viewing of image results that many parents would want to protect their children from.

Is there an expected fix for this problem?