Ajuga die back

Hi, I sent an enquiry in mid June to ask if you could help determine what the problem is with the Ajuga in my garden. All of a sudden the leaves became distorted and curled and shriveled. No other plants in the same area are showing any signs of a problem. I have attached photos. Will send another message as it appears that only 1 photo can be attached per message.
Clay soil, afternoon shade, established planting. Weeping Japanese Maple, Ferns and Hostas are also planted here and none of them are showing any problems, so it is not a lack of water issue.