PVS-Studio warning V547 for ICU

U_CDECL_BEGIN static const char* U_CALLCONV
_processVariableTop(....)
{
  ...
  if(i == locElementCapacity &&
     (*string != 0 || *string != '_')) {
    *status = U_BUFFER_OVERFLOW_ERROR;
  }
  ...
}

This suspicious code was found in ICU project by PVS-Studio static code analyzer.
Warning message is:
V547 Expression '* string != 0 || * string != '_'' is always true. Probably the '&&' operator should be used here. icui18n ucol_sit.cpp 242

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