Disunited canter on one rein

[GrumpyHero]

My loan boy keeps going disunited on the right rein on the lunge .. He gets his lead right but his back end is all wrong. He'll try and correct himself but ends up on the wrong canter lead (but his legs are right) then he'll switch back to disunited then sometimes corrects himself properly. He's fine on the other rein and seems to pick up the right lead every time even though that's his bad rein (he's a lot stiffer down that rein)

His saddle is irritating him so i'm not riding in it until i can get a fitter out. I've been given an adjustable wintec to borrow for now but I'm not 100% with the fit of that either - hence the lunging and why I've noticed this more recently!

I've only noticed it on the lunge and never had any comments when riding about him being disunited at any other time.
Is this just a balance/lack of schooling problem (I'm a happy hacker!) or could there be something more?

:redface3: Please be nice I only want what's best for him!

 

[nikicb]

If his saddle has not been fitting him properly it will probably have caused some tension/bruising in his back. If he was mine I would call my vet to chat it through and either get the vet out or someone like a physio to check him over so I knew there was no physical reason before I did anything else.

 

[HashRouge]

It could be a balance problem, but it could also be a sign of something else. I know that going disunited can be a sign of sacroiliac pain, or sometimes kissing spines. It's odd though that he does it on the lunge but not when being ridden. I'd be inclined to get the vet to come and have a look, to be on the safe side. My own mare started going disunited in canter and I thought it was just balance issues, but it turns out that she has SI problems - I really wish someone had told me to phone the vet sooner, instead of faffing about with physio etc!

 

[Birker2020]

My horse did this and had spavin. I would suggest getting the vet out to assess him and do a lameness evaluation. If its spavin its not the end of the world by any means.