Q.Do I Have Poorly Busy Lizzies?
Hi, I bought 40 plugs of Busy Lizzies, some of them have dark red / purple / brown funny shaped marks on the underside of their leaves – see photo. Please help! What is it? Is it just a normal pattern on the leaves or is it diseased? Many thanks.

Certified GKH Gardening Expert
This appears to be the beginning of an infection! Likely the plugs have been kept a little too moist, and too close together.
I would recommend a fungicide/bactericide. These articles will help:
https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm
https://www.gardeningknowhow.com/garden-how-to/info/applying-bactericide-to-plants.htm