Also confirmed here with 1.3.80. The first time I used it the two numbers (that in the Tranfers tab and that in the "status bar" at the bottom of the window) were in perfect unison. The second time I used it, the number in the status bar was pretty much exactly twice that shown in the Transfers tab. The Transfers tab's value was the accurate number.
I just upgraded to 1.3.80 yesterday and have used it twice. The first transfer had matching numbers on the Transfers tab and the status bar (if that's the correct term) at the bottom of the window. However, my second transfer showed an exact doubling of the actual transfer rate in the status bar, while the Transfers tab showed the correct value. Essentially, I'm confirming what the OP wrote. Running Win 7 / 64, by the way.