Hey Andy,
I've bred a number jags over the past few years.
What I've found is that different stresses bring on the symptoms of the neurological disorder in differing severity (no link between type of stress to severity of neuro).
All Jaguar mutation animals will have the ability to display symptoms and while some do not exhibit these symptoms others will.
Excess heat will stress most animals as you are aware and with this stress some jags will exhibit the disorder.
I have yet to see any of my jags exhibit symptoms that are directly triggered by cooling for breeding.
I find that most of the offspring I have hatched do not display neurological disorders, but does the stress of transport bring it on? Possibly. I have recently hatched twin jaguars this season. They are identical and quite small compared to their siblings. One of the twins displays a head wobble while the other is bullet proof, so far.
So I think it is very much determined on how the individual jaguar animal handles stress, results in the severity of neurological disorder.
Of the 30 odd jags I have at my place at the moment, only 3 display neuro and all of them are very minor, being a head wobble or just move differently when handling.
If you're wanting a pet snake that you want to frequently handle, then a jaguar mutation is not for you. They are best as a display animal in my opinion.