I heard Looking Glass yesterday as well and the Skymaster station responded to him.
Couldn't tell what was going on, but was rather busy, similar to an amateur radio contest at times. I heard two stations ask if this was real world or an exercise. I didn't hear a response the first time and the station responding at the second time was too weak here. I also heard Icehouse yesterday (in addition to the others already mentioned).
Heard frequent EAMs, with other stations (assuming they were aircraft by their callsigns) calling Skymaster with 4 item messages in between the EAMs and sometimes over the EAMs.
The EAMs were by at least three different callsigns and seemed to be of varying signal strength. The signals on the other HFCGS were different than usual. Usually on normal(?) ones, I get an echo on 11175 and a bit weaker on 15016, and 4724 is very strong with no echo. Yesterday, they were of sufficient strength on 11175, a little weaker on 15016, and completely absent on the other freqs (4724, 8992, and 13200). Clearly using different transmitters that usual.
The aircraft with 4 item messages weren't simulcasting on other freqs, I only heard them on 11175. I wasn't checking the other freqs during quiet times to see if any showed up there, I'd only check when 11175 was active and for parallel activity.