Tangent space vector displacement with Autobump

[olygraph]

Looks there is something wrong with the autobump with a Vector displacement in tangent space. Works perfectly in world and object space thought.

On the left it is a Tangent space vdm exported from zbrush, with Autobump enabled.
On the right is a World space vdm exported from same zbrush model with Autobump enabled.

Works perfectly on the world space one, but the tangent has a lot of shading issues. Below ill post more example of extreme issues.

Here is same as above, but autobump is turned off on the tangent space vdm.
On the right side is still the world space vdm with Autobump still enabled.
Both have no issues.

Here is the geometry used to create the displaced geo above in maya.

(first = world space vdm - autobump off
second= world space vdm - autobump on. )
Above is a VDM in world space with a bump mixed to it. It works flawlessly with auto-bump and few subdivision level.
This is awesome for optimized renders and accurate high resolution geometry representation. Downside is that world/object space it is limited to not deformable geometries.

Here is zbrush diagnostic file. Just to show how autobump can create big issue in more extreme exemples.

Is this fixable? Would love to have tangent space VDM working with autobump. Otherwise we have to subdiv a LOT and it is not really an option when used with high frequency details.