"not properly understood" is correct and usable in written English.
You can use this phrase when you want to indicate that someone has not grasped something in the way that it was intended. For example: Some of the more complex concepts presented in the lecture were not properly understood by many of the students.
In an ironic conclusion we are shown what happens when symbolism is not properly understood.
Vivid Economics, a consultancy, has recently shown that the true value of the Green Belt is not properly understood.
But climate sceptics, who have long argued that natural processes are either underestimated, or not properly understood, will not be surprised at this scaling back of expected warming.
He deplores "the way in which banking became a merry-go-round of instruments which were not properly understood or properly priced – that's obviously a moral problem".
It is the first big retrospective of an artist who has certainly been neglected and perhaps not properly understood since her death.
Only to emerge feeling that their account of being harmed has not really been heard or, at least, not properly understood.
Mr. Romney and his aides quickly corrected his remarks, saying he strongly supports the Senate amendment, and had not properly understood the question.
Metabolic syndrome is found in a sixth of the American population".Syndrome" is the medical term for a collection of symptoms whose common cause is not properly understood.
"They have not properly understood what a mass audience wants to see in a newspaper".Tabloids have an edge when the rest of the media is conformist.
In an interview with Forces TV, the former prime minister, who attended the service, said that even now it was not properly understood just how much more there was to be done.
This is an approach – largely due to the efforts of our more progressive continental cousins in Scandinavia, Germany and the Netherlands – that is still not properly understood by many UK politicians and civil servants (as George Monbiot explained recently).
