These spots appeared seemingly overnight. Can be found on leaves top/bottom. Spread to a lower branch/leaves on an adjacent plant. Would appreciate any feedback.
That's definitely not leaf septoria. The plant looks very healthy. Some of the spots seem to be holes. Have you seen any pests hanging around? If not, I've seen leaves on my outdoor plants get marks on them from the wind blowing hard and causing them to hit a branch or even each other. Could also be a very slight Ca deficiency, I guess. Are you using filtered water?