During my test, it was observed that when there are 2 logical nodes with same string repeats, ( such as almGGIO1 and almGGIO10) in those cases, these 2 below functions add the DOs from almGGIO1 to almGGIO10. and model discovery will show invalid DOs under almGGIO10. My test was done in 1.5 version, I think this change is relevent in current version also.
IedConnection_getLogicalNodeDirectory
IedConnection_getLogicalNodeVariables