I did a step-by-step diagnostic this morning and playing the speakers individually or grouped in Roon has the same effect. When the wifi zones are ungrouped all is well with the wired zones, and when added to the group, the system poops out. I cannt easil hardwire the wifi speakers, and since this option doesn’t exist in my home, it’s a moot issue. I came across this: Bluesound wireless seems to be the problem
It seems to be an inherent issue unfortunately, though I am still perplexed by the fact that I had several weeks of perfect performance with no system modifications (unless there was an automated firmware update I’m unaware of which made a mess). Thanks for any observations.