The front leaf looks like it might have been sunburned. Sometimes the damage takes a few days to appear. Cold can have the same effect. But since it seems to mostly be that one leaf, I do strongly suspect that it got a bit cooked.
Put it under shade. It doesn't need too much light.
And don't wait for the medium to get dry. Considering the pot size, try for a start to water it once/week (that's what I do to mine under a low humidity, i.e., 30% winter and 15% in summer).