Yes, there are detached controls in the preset.
But I can remove them all (in GUI) and that is persistent (saved/loaded preset).
So sorry, what is the problem?
Just to avoid misunderstanding: Logical Controls are normally bound throw Hardware Context to Hardware Control. Logical Controls don't have names on there own, the name is always '' (Empty). Hardware Controls are named directly. Hardware Contexts by default have name '' (empty), since most of the time there is just one. Even with one it is possible to define Hardware State Set and so name the Context, when using more then one that is i kind of "must" since with empty Context name Logical Controls will have the same name for all contexts, that will be really confusing.
When Logical Control is Attached, it gets the name of Hardware Control + Hardware Context to which it is attached. Once Detached, it again has no name. In the GUI, detached Logical Controls are labeled as "Detached <number>".
Calls and Actions are bound to the Logical Control directly. When referenced, Logical Control can't be deleted. But it can be Detached at any time.
PS. I don't know if someone except me (and only for my MPK Mini) have ever used multiple Hardware Contexts. At the end that complicated schema just provides a tiny improvement in behavior of some Value Action modes, which use "previous" known physical control position. And only in the case the control can send different MIDI messages (and so used in different Logical Controls).
The implementation is so complicated (with "Contexts" and "States") since in general controllers don't inform the DAW that hardware layout is changed on the device. So AZC has to guess, using all hints possible. Hardware layout is normally change many controls, so once we "detect" one of them is in different layout, that is a hint other have changed the layout as well. So, there must be some "common" (for the group) way to save the layout, that is "Hardware State Set". There can be different independently switchable groups of controls, and they can overlap (f.e. the layout of knobs is switched or the layout of knobs and buttons is switched), so more then one Hardware Set may be required to mirror complete layout of the device and move then one State (from different Sets) can be associated with one Logical Control.
Theoretically I could add Hardware Context functionality into Logical Control (since that association is one to one), but I am not sure that will be simpler to understand. Also when defining all that, I was moving MIDI assignment on the device between hardware layouts. And so a possibility to change Hardware Context for Logical Control was useful (without redefinition of the Contexts).