Perhaps environmental. But too little damage to affect plant.

Thanks jean0001a. Should I just leave it, or perhaps would be safe to remove that leaf?

either or salavene. It's still performing, but you have enough foliage there that prettying it up by removing wouldn't harm it.

Kevin

Thanks guys! I removed it just to be safe... Lots of new foilage on the way as well (been a few weeks since repotting and coming along slow, but nicely)!