Does my Pittosporum have a fungal disease?

We got this mature pittosporum golden king plant last year. It’s been very happy, but I’ve just noticed some of the leaves are turning yellow and dropping off. There was also one branch in the middle of the shrub with all dead leaves which I just removed. 

Is it a fungal disease? If so, what’s the best method of treating it? 

My neighbour’s cyprus tree (image below) has developed problems over the winter - I wonder if that disease has spread to this one? 

Any help would be v much appreciated.

Thanks