Blueberry leaves are dropping affected by disease

Yuliya starts with ...
Hi guys,
Misty and Biloxi dropping leaves affected by this yellow-orange spotted fungus (?). Soil is acidic and up until 1 month ago they were flowering like crazy and were very happy. The other varieties don't seem to be affected, despite the fact that they all are in a containers very close to each other.

I've removed the affected leaves, but I'm sure there is still plenty of that substance around, so it's probably going to come back...

Thanks everyone!

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