Solved in https://github.com/Slicer/Slicer/commit/ea356afb352766c74c7fe23720c6130669758841

Excellent, thanks! I'll test and close

Johan, did you test? Please add a comment before you close! Also, according to the process, only the person who created the issue is supposed to be able to close it. Thanks!

I'll un-close it until I can test and close.
As Johan havent' answered, I assume he hasn't tested. According to the official workflow, the reporter needs to close, so after testing, I will.

Unfortunately the issue is still present (in revision r25994). To reproduce:

import SampleData
sampleDataLogic = SampleData.SampleDataLogic()
mrNode = sampleDataLogic.downloadMRHead()
mrNode1 = sampleDataLogic.downloadMRHead()
len(getNodes('vtkMRMLScalarVolumeNode').values())
2
mrNode1.SetName('MRHead') # Make the two nodes have the same name
len(getNodes('vtkMRMLScalarVolumeNode').values())
1

This has been fixed. getNodes returns a map where each value is a list. This works:

len(getNodes('vtkMRMLScalarVolumeNode*', useLists=True).values()[0])