The manner in which they were kept over wintr might suggest something. In your zone I suppose they were left in the ground--possibly heavily mulched. Such leaves that pop up in spring, might have insects that hide in such mulch and the leaves are thought a tasty meal.
Brown spots can occur if watered too heavily or possibly where sun can directly hits the leaves when wet.
Insects that do attack outdoor plants, much like they do houseplants, might be from aphids, whiteflies or mealybugs.

Tigridia pavonia likes to come into the world in a cooler spot and grow into the sunlight. Stakes might be used to support the stem if necessary.

Thanks Jeannie for your reply which I have just read. There are no sign of insects, so I think probably it has been the sun on the leaves when they were wet. They are growing so I am pleased about that.