Describe the bug

I have the a series comprising 413 dicom slices the "ImagePositionPatient" tag for the slices are :
slice 1 : -216.500 \ -216.500 \ 70.000
slice 2: -216.500 \ -216.500 \ 68.750
.....
slice 413 : -216.500 \ -216.500 \ -445.000

The "ImageOrientation" is the same for all tags :
(0020,0037) Image Orientation Patient 1.000000\0.000000\0.000000\0.000000\1.000000\0.000000

I read these slices with the Image Series Reader:

reader = sitk.ImageSeriesReader()
reader.SetFileNames(dcm_list)
image = reader.Execute()

Reading the slice from the last to the first (bottom to top), the metadata of the final 3d image is inconsistant with the values of the dicom tags :
image.GetOrigin() -> (-216.5, -216.5, -445.0) seems OK
image.GetDirection() -> (1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, -1.0) not OK last vector should be 1 instead of -1

if I put the slices from the first to the last I get correct results :
image.GetOrigin() ->(-216.5, -216.5, 70.0) seems OK
image.GetDirection() -> (1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, -1.0) now it is OK since we are reading from top to bottom

so depending on the order of the slice given, one give a coherent result in term of metadata and the other does not.

My understanding was that the code computed the 3d direction matrix with both the "image orientation" for the first two axes, and the vector defined by the vector separing the "image position patient" of the two first slice given. In that case it should be 0 / 0 / 1 when reading the image from bottom to top and 0 / 0 / -1 from top to bottom but last vector is always 0 / 0 / -1

To Reproduce
Hard to reproduce without sharing the dcm files itself, on request it can be done

Thanks !

Here are the full information of the final 3d image for reference :

Image (0x40bcd700)
  RTTI typeinfo:   itk::Image<int, 3u>
  Reference Count: 1
  Modified Time: 16338
  Debug: Off
  Object Name:
  Observers:
    none
  Source: (none)
  Source output name: (none)
  Release Data: Off
  Data Released: False
  Global Release Data: Off
  PipelineMTime: 1807
  UpdateMTime: 16334
  RealTimeStamp: 0 seconds
  LargestPossibleRegion:
    Dimension: 3
    Index: [0, 0, 0]
    Size: [512, 512, 413]
  BufferedRegion:
    Dimension: 3
    Index: [0, 0, 0]
    Size: [512, 512, 413]
  RequestedRegion:
    Dimension: 3
    Index: [0, 0, 0]
    Size: [512, 512, 413]
  Spacing: [0.845703, 0.845703, 1.25]
  Origin: [-216.5, -216.5, -445]
  Direction:
1 0 0
0 1 0
0 0 -1

  IndexToPointMatrix:
0.845703 0 0
0 0.845703 0
0 0 -1.25

  PointToIndexMatrix:
1.18245 0 0
0 1.18245 0
0 0 -0.8

  Inverse Direction:
1 0 0
0 1 0
0 0 -1

  PixelContainer:
    ImportImageContainer (0x40f65de0)
      RTTI typeinfo:   itk::ImportImageContainer<unsigned long, int>
      Reference Count: 1
      Modified Time: 1875
      Debug: Off
      Object Name:
      Observers:
        none
      Pointer: 0x7fdb14418010
      Container manages memory: true
      Size: 108265472
      Capacity: 108265472