The file 2.dcm is an invalid DICOM. See spec:
http://dicom.nema.org/medical/dicom/current/output/chtml/part10/chapter_7.html#para_c820193f-7a41-4470-a0f4-98b88433b403
It cannot be more clearer than that ('shall' is used, not 'should'):
[...]
Values of all Tags (0002,xxxx) are reserved for use by this Standard
and later versions of DICOM. Data Elements with a group of 0002 shall
not be used in data sets other than within the File Meta Information.
[...]
However DataSet does contains an element from Group 0002.
Let's first fix the software which write this buggy DICOM, then fix
the software that accept this invalid DICOM.
