Pyracantha Saphyr Rouge HELP

Hello,

Sorry if this is not allowed.

We’ve got 300 pyracantha in a row in work, 90 of which have all started to go like this – it’s not every branch but it’s a lot. The inside of the stems are green.

We purchased Saphyr Rouge to avoid scab and fireblight as much as possible but less than a year after being planted, this has happened.

Please let me know what you think it could be. I did email the people who created the cultivar but they couldn’t help me, sadly.