Ok thank you, the problem is exactly the same with all my lenses, it just depends on the outside temperature (when colder, the problem disappears) so I think it's just the camera...
In particular conditions, I noticed strange effects on some of my pictures which could be the result of a crooked mount...
I hope it's not the case, but it seems that I will have to send it for service anyway 😕
Thank you for replying ! 😄