Maybe an infestation of some kind? Easy to see on jade leaves because smooth green area. Anything similar on your other plants, which may be harder to see if foliage is not so smooth. I would be tempted to separate the jade from other plants if only jade is looking weird so as to not spread possible infestation. Plants crammed indoors with other plants leave the door open for spread of infestation if one infested plant is present.
I would take solution of dish soap in water and use on paper towel to wipe off the leaves and see if the spots can be removed (possible insect sitting on there) and then monitor if leaves change appearance again. If toweling off does not remove spots, it may mean that the spots are damage done to the leaf by something. Look closely at stems and under leaves and at crevices of leaf/stem to see if you can see a culprit. If not, damage may be due to some sort of fungus?
