Express and Express + multicasting on network

I have a Express + and a Express; both units are multicast across my network - continuously sending data.  This started after the upgrade to 12.0.0. The Express + was upgraded on 5/11/23 and the Express was upgraded on 6/2/23.  If I unplug (AC) them then, all the traffic goes away and network if fine.  the Express + build is 4184 and the build on the Express is 41-86-51.