"Undo" does NOT Remove device. FX Rack (AU's) Bug

[kineticUk]

The bug ... (Noticed after loading certain AudioFX rack's using AU's)
After inserting a FX Rack (Containing AU's only), if I then go to undo (Edit Menu), it shows values instead of "undo Insert". It actually shows "undo change value" I think. Undo seems to just step back through Fx values, maybe as if I had just tweaked all the plugs controls when originally making the rack. It does NOT remove the inserted device for some reason ???
I know it happens when I use a certain saved Rack I made. And also this Audio FX rack contained AU not Live Fx. Most of my Racks contain Live Fx not AU's and these do not have problems as far as I have seen.
I reported this to support direct a while ago but would like to know if anyone else has noticed this strange behaviour (Bug).
Hope this is clear enough. (Used Version 6.0.5). Thanks.

[kineticUk]

Ableton,
I have found a Rack preset that uses AU and I can reproduce this bug 100% of the time with the Rack.
Please let me know if it would be any use sending this to you ?
Thanks

[Amaury]

Hi,

Yes, it would be useful if you send me the exact description of the problem including which plugin it involves at [email protected].

Thanks a lot!
Regards,
Amaury

[kineticUk]

More on this cause I've tested more and I think I've sussed out the problem.
If an audio FX rack contains AU's (Only AU's or Live FX plus an AU), and you load the rack into a track...then the bug.
Instead of the Undo Apply Preset Option, you undo parameter changes. It seems it deconstructs the rack as I said above.
I have sent Amaury a Rack which can be used to reproduce this, and I also have more presets which contain different AU's...all reproduce this bug.
Hope this helps fix the bug or find out the problem.
Thanks.