Still exists in MC version 1.10.
I can also confirm this issue.
Confirmed for 1.9.2
In addition, the south east rule can be difficult to understand? Is there any reason why this is necessary in the game? Surely it would be easier to eradicate it overall?
Yes, there is no evidence of this being patched in 1.6.2
Tested with Shulkers in 1.12, and this bug still exists; the Shulker gets loaded where it got saved with structure blocks.