Issue was the USB-C cables that were supplied with the monitors. Switching from 1.8 m Gen 1 to 1 m Gen2 took care of it, no more mic drops.
Anyone else using these otherwise wonderful video conferencing monitors? They are excellent for home offices and huddle spaces, combining an USB-C hub, webcam and mic in a single package. Though, recently we have been experiencing constant issues with the microphone in the display cutting out anywhere between 3 and 45 minutes into a Teams call ("You're microphone isn't working. Switch to a different device or try reconnecting this one.") Users of Zoom have been reporting the same issues. We have singled the root cause down to the Realtek High Definition audio driver as installed by Dell Command Update (or directly from Dell.com). If we avoid installing this everything works just fine, but it is kind of a downer not being able to depend on Dell Command Update for staying current. Issue can reliably be reproduced on all our most recent devices (Latitude 5x00 through 7x30), and it's the same whether we run the Dell factory or our own cooked image. Dell have unfortunately been of no help so far, except replacing the display (which did nothing). Hopeful that anyone else has seen this and may provide a suggested solution.
C3422WE, Realtek, microphone cuts out