When we have the following source code:

/// docu of class foo
class foo
{
public:
  /// @param arg1: this is the version with colon directly attached to arg1
  void fie1(int arg1);
  /// @param arg1 : this is the version with colon separated from arg1
  void fie2(int arg1);
};

The result is that in the parameter documentation for fie1 the argument is given as:
arg1,:
but no warning is given, so it looks like doxygen sees arg1 as the argument. Furthermore it is strange that a ',' is added.
(A default Doxyfile is used)