Is the soil rather damp around the plant?
Damp is hard to quantify but I would say no, it usually dries somewhat between watering.
The last couple of weeks it has been more wet more regularly due to rain, though.
Here's a new photo. You can still see whatever those marks are under the leaf in the center, but they haven't gotten worse and do not appear to be present on newer growth.
There is a lot of new growth overall and it looks pretty OK. But I am still not sure what made last year's leaves turn brown en masse. Underwatering was my best guess so if anything, I may be overwatering now.