PVS-Studio warning V576 for Micro-Manager

int MP285Ctrl::Initialize()
{
  ....
  unsigned int nUm2UStepUnit = MP285::Instance()->GetUm2UStep();
  ....
  sprintf(sUm2UStepUnit, "%d", nUm2UStepUnit);
  ....
}

This suspicious code was found in Micro-Manager project by PVS-Studio static code analyzer.
Warning message is:
V576 Incorrect format. Consider checking the third actual argument of the 'sprintf' function. The SIGNED integer type argument is expected. MP285Ctrl.cpp 253

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/