Wyze sense integration with Alexa: no motion detected fails

My issue seems related to this one; raising a new thread as there has been no activity on the former for 4 months.

As of a few weeks ago, Alexa is no longer receiving or acting on “no motion detected” events from my Wyze motion sensors. This is entirely reproducable. I have 3 sensors, all triggering Alexa routines for both “motion detected” and “no motion detected”. All of the “motion detected” triggers work with very high reliability. The “no motion detected” triggers used to work similarly reliably; now none work at all.

The problem appears to be in the Wyze->Alexa connection. The Wyze app reports the sensors showing no motion detected accurately. Triggering the Alexa routines manually triggers the appropriate actions. I have tried (many times) deleting/readding the sensors to Wyze, recreating the Alexa routines etc. with no success.

To recap: motion detected triggers Alexa beautifully; no motion detected doesn’t work at all.

Anyone else experiencing this or know how to fix it?