I think it is just some physical damage.....those big, fleshy leaves are very easily damaged. I grow a couple of different cultivars but outside and notice that the foliage can easily be distressed by a rough touch, hail or excessive wind. Or more specifically by slugs and snails, which absolutely love to feast on these plants! But no diseases or even minor fungal issues have ever bothered them.

btw, this plant was reclassified out of the Ligularia genus some years ago (1939!!) and is now Farfugium japonicum.

Looks like the result of a compromised root system from over-watering. Does your pot have a drain hole? Try using a "TELL" to check soil moisture levels. Buy a 1/4 or 5/16" wooden dowel rod (any hardware or home imp store), cut it in half, and sharpen all 4 ends in a pencil sharpener. Use the "tell" by sticking it deep into the pot. check the tip for muddy stains or obvious moisture, and water only when the tell comes out nearly dry. Don't worry, the tell will do far less damage to roots than will over-watering.

Al

It's pretty darn hard to over-water a Farfugium :-) These can actually be grown in standing water...as in a pond or pool or bog garden....and prefer consistently moist to wet soils. Do not allow to dry out!!