That's a beautiful plant.
Even though everything has stayed the same, obviously something has changed. The easiest thing to check is how well the soil is hydrating. Water as you normally do. Does the water run through quickly? Can you dig your finger down into the soil and feel moisture? Use a bamboo skewer to check for moisture content at the bottom of the pot. Shove it down to the bottom of the pot, leave for a couple minutes and pull it out. Is it wet or dry? If you can't see or feel moisture, the soil has become hydrophobic.
There are two ways to try to solve that problem, water multiple times a few minutes apart until the soil rehydrates or soak the pot in water up to its rim until the soil rehydrates.
