This phrase has become a cliché. For this reason it has been necessary to invent the expression "under active consideration", which is itself on the way to becoming a cliché. It is an old civil service joke that "The matter is under consideration" means "We have lost the file", and "The matter is under active consideration " means "We are trying to find the file". These expressions should be avoided if possible, though it may sometimes be difficult to do without them.