After 20:00Z all HF-GCS stations commenced using the term mainsail, rather than the usual Andrews/Offutt etc. The only exception seemed to be Offutt, who was working RECKLESS for a patch. As soon as the patch terminated Offutt also began using mainsail. There seemed to be a short period where the test counts reverted to Offutt/Andrews, before returning to using mainsail. I suppose it remains to be seen if this is permanent or temporary. Did sound strange though, "Aircraft calling mainsail, this is mainsail, how copy"