Is it just the oldest leaves? As long as new leaves are coming in at the same pace, that's normal for palms. Part of the process of the trunk aging & turning woody. If that doesn't apply to the kind you have, which is not one of the palms that I also have, I'm sure somebody will point that out to us. Also seems to be on the floor, where the coldest air in the room is, like the Aglaonema in your other pic. Tropical plants don't abide cold roots well, especially if soggy @ the time.
