ID 310737 - Nuke crashes when moving a user track in the camera tracker sequence in stills mode.

Problem summary
Nuke crashes when moving a user track to a different frame in the camera tracker sequence in stills mode.

Customer reported version
nuke.11.0v2

Customer reported platform
MacOS 10.12

Steps to reproduce

1) Import some individual Exr images (I used 5 for my test).

2) Select them and then create an AppendClip node, linking each image to the AppendClip node. 

3) Create a CameraTracker node and set the Source from Sequence to Stills connect that to the Append Clip node. 

4) With the CameraTracker selected, create a user track using the hotkey (Cmd+ Alt+Left Mouse)on Mac, (Ctrl + Alt + Left Mouse) on Windows/Linux.

Workaround
Instead of using the hotkey to generate your tracks, manually click the "add track" button to create your tracks and work from there. 

Reproduced by support
NukeX 11.0v2 - LinuxCentOS 6.9 - Windows 7 - MacOS 10.12
NukeX 11.0v1 - LinuxCentOS 6.9 - Windows 7 - MacOS 10.12
NukeX 10.5v6 - LinuxCentOS 6.9 - Windows 7 - MacOS 10.12
NukeX 10.5v1 - LinuxCentOS 6.9 - Windows 7 - MacOS 10.12
NukeX 10.0v6 - LinuxCentOS 6.9 - Windows 7 - MacOS 10.12
NukeX 10.0v1 - LinuxCentOS 6.9 - Windows 7 - MacOS 10.12
NukeX 9.0v9 - LinuxCentOS 6.9 - Windows 7 - MacOS 10.12
NukeX 9.0v1 - LinuxCentOS 6.9 - Windows 7 - MacOS 10.12
NukeX 8.0v7 - Unable to reproduce
NukeX 8.0v1 - Unable to reproduce
NukeX 7.0.10 - Feature did not exist

Earliest version tested
NukeX 8.0v1

Expected behaviour
The User Tracks would be able to at least create keyframes on the next frame via user tracking.

Actual behaviour
Nuke Crashes when the frame is changed despite it being a user track.