Mineshafts are not generated.

In the wordgeneration mineshafts are not created.
I tried it with seed i used in 1.0.5 - at all places no mineshafts where they were before.
The same on Windows 10.
I was looking in other seeds also - knew and known from the net.
Was also looking with X-Rax
-> no mineshafts at all. Not on Android and not on Win 10.