Ornamental pear problem , pest ?

[Misbeth]

Could anyone please help me as to why why ornamental pear is turning red . I have two of the same and it’s only one that is doing this. I have attached a close up of the leaves .
Thank you
Beth

 

[Misbeth]

Photos of ornamental pears

 

[cpp gardener]

A little background on their care and conditions would help. Sun/shade, watering, fertilizing, noted pests/diseases.
Picture#4 looks like some other plant. Maybe Star Jasmine?

 

[Misbeth]

Hi thank you for replying much appreciated .
Definitely not star jasmine I have that as a climber throughout the garden .
I fertilise with rustica plus which is only recent . The pear tree did this exact same thing last year and it was normal in colour in the previous years . It is in mid afternoon sun until sundown wind sheltered . The last photo is the other one which doesn’t have red leaves nor the marks on the leaves .