Having just come off the golf course (walking) on a very humid day, it doesn't feel like I sweat any less.
I had the same problem when I dropped into the 140s. People constantly asked me if I was ill.
I had always lost water weight playing golf, but it came right back on. I started riding again about 10 years ago after a 30 year break and had the same experience. But after a couple of months the pounds didn't all quite come back. After a couple more months, I was down about 20 pounds. Hadn't been at that weight since I was 20. With all the comments it was a bit worried, but my doctor said I seemed fine and I stabilized there.