In the latest preview version, the problem cannot be reproduced.
As I am working with the sources of 4.10.2 for my project, it would be very interesting what was changed for the problem to be gone as I will have to apply the solution as a patch in my version. I can go through the commits myself, I just would need a hint where to start my search. Thanks
4.10.2 uses an older version of ITK for file IO, and probably a lot has changed. You could go back and see if the problem could be reproduced in pure ITK and then perhaps backport whatever changes are needed. But more sustainable long-term (and maybe easier) would be to port your project to the latest Slicer.
Note that we will soon (in maybe a couple of weeks) release Slicer-5 and deprecate Slicer-4.10. So, I would not recommend to spend time with backporting any fixes, etc. to Slicer-4.10 but rather spend that time with updating to latest Slicer-4.11 (that will become Slicer-5) and test/fix things.