Why is my sensor not updating my Gauge Card?

ESPHome
1

I have an SDM230M sensor:

sensor:
  - platform: sdm_meter
    update_interval: 10s

    phase_a:  
      current:
        name: "ESP32.SDM230M Current"
      voltage:
        name: "ESP32.SDM230M Voltage"
      active_power:
        name: "ESP32.SDM230M Active Power (P)"
        force_update: true

… which will not show an update in the Gauge Card for hours at a time?
image

However, if I request the log output from the SDM230 sensor in a second browser window, the log output AND the Gauge Card update every 10sec as hoped for.
One small clue? The force_update: line is not new. I guess that when I added it, I was satisfied with its performance?
Has the force_update: stopped working?
Regards, Martin