I noticed the same thing today, seemed to start during a severe thuderstorm.
One station reported to Fire Alarm that they didn't recieve the call on the "new radios",
but that everything was coming through on the old system.
As I'm writing this Engine 18 is being paged and the old HI-LO tones are being sent,
not shure why. The MOSCAD paging on TG 00336 is also active and digital voice is
working fine, strange......