Plant Pepperomia in a pot with ample drainage holes, using an orchid potting mix, then place the plant in bright indirect light. Peperomia plants require little in the way of attention. You only need to water them when the soil is dry. Plant food or fertilizer is rarely necessary

wonder why no answers.. hmmmm..

my first inclination was to say cold damage.. but you immediately ruled that out.. so i am stumped ...

ken

It's an inherent/ normal genetic trait of Peperomia caperata.

There are fungal infections that live in plant's water conducting tissues (xylem) which produce a toxin that can cause the leaf epidermis (skin) to separate (or delaminate if you prefer) from subcutaneous leaf tissue. The separation changes how leaves refract/ reflect light, making leaves look silver, but I seriously doubt there is a fungal infection of that type in play here.

Al

In my long experience with dozens of species of Peperomias, areas of edema like this are usually a response to an overly heavy soil watered too often. Go really dry between waterings, especially in the short days of winter.

I don't usually see cold damage on P. caperata as it can take near freezing without damage. We grow it outside in San Francisco.