job output: "clear output & reset programs" followed by "save output" saves output that's been cleared already

As stated over on doom9.org:

If I mux and then clear the output, it removes the output from the window. If I mux again, the new output shows in the window, but if I then save the output (as you suggest), the file contains the output from both muxes. It seems to keep everything since the program was last closed.