On the usual 4625 kHz, the WebSDR does pick up a very weak and raspy audio tone at 250 Hz with a possible harmonic at 500 Hz. This tone is becoming louder at 1700 UTC, and its timing and waveform are very similar to the "buzz." Is this a lowered gain or a second transmitter?
In any event, we can safely conclude that either something's still being emitted on this channel, or that someone's playing around.
UPDATE 1717: It's definitely the same tone, just not as loud. Conditions, lower gain, or is there actually a second transmitter as some have theorized?