That does not look good. I'm not a jade expert but it looks like a fungus infection to me. Is the air in good circulation around the plant? Is that the only leaf with the problem or is it wide spread?

It’s in an open room with a southern exposure window. I water about once a month in the winter.

This plant and another have the spots.

what do we use to treat a fungal infection?

It may be fungal infection, or possibly oedema/edema. Some jades are more susceptible than others. Which jade is it?

If oedema, that is a disorder - plant taking in more water than it can transpire. For a fungal infection use a fungicide (like flowers of sulfur).

Good air circulation as Rob mentioned helps; maybe use small fan to help. I prefer not to wet leaves too much when watering, rather potting mix.

These are plants I got from Mike. I’m not sure if the name. the jades are in a gritty mix. In the winter I water about once a month. I can’t imagine it would be edema.

I’ll check out the fungal treatments.

thanks for the help.

IME that sort of problem is one of cultivation. Also, as long you’re giving it warmth, light, and the rest, watering should occur at least 2x a month now-it is their growth time.