I did get a few responses from a Facebook group, one from a doctor and one from a patient who has become a bit of an expert:

Here's the first comment:

C2-3 looks unstable.
C3-4 ADR not good
C4-5 ? Looks deceptively normal
C5-6-7 fusion achieved in kyphosis
Overall scoliosis is present
Get your DMX Fluoro
C3 body has changed its shape that’s why C 2-3 is unstable, C3-4 ADR is working but not in a good position because the upper end plate of device is slightly anterior, C4-5 is also moving a lot and the due to the fusion below which is in kyphosis. Overall the dynamics of the cervical spine has changed.
Get an MRI to see you C2-3, C4-5 and you may also need a CT Myelogram to see C3-4

Here's the 2nd comment, which is concerning to me and I'm not sure how they are seeing it:
I honestly really think you have a C1-C2 rotation above the operated levels. This could just be that you need to see an atlas orthogonal upper cervical chiropractor who can unrotate your C1-C2 with a very precise instrument or you also possibly have instability in the upper neck. Do you have an x-ray that is frontal with your mouth open? And that type of x-ray you can see if the Atlas and C1-C2 is rotated.