Q.Trumpet vine disease
What is wrong with this trumpet vine? It’s starting to spread to my other trumpet vines.
This could be a fungus disease, as you mention it spreading.
Remove and prune out disease plant material and dispose of.
Check for insects or any other signs of plant damage.
Here are some links with more information.
https://www.gardeningknowhow.com/ornamental/vines/trumpet-vine/growing-trumpet-vines.htm
https://www.gardeningknowhow.com/ornamental/vines/trumpet-vine/trumpet-vine-losing-leaves.htm
https://www.gardeningknowhow.com/ornamental/vines/trumpet-vine/bugs-on-trumpet-vines.htm
https://www.gardeningknowhow.com/ornamental/vines/trumpet-vine/diseases-of-trumpet-vines.htm