ESS AcPowerSetPoint resets to default 50W sporadically every few minutes despite Cloud MQTT writes

I’m using ESS with “Optimized without BatteryLife” on a Victron Ekrano GX. Every couple of minutes (2-10 minutes), /Settings/CGwacs/AcPowerSetPoint gets reset to the default value of 50W. I’m writing the value via Cloud MQTT (W/<portal_id>/settings/0/Settings/CGwacs/AcPowerSetPoint) from an external server, but only every 15 minutes. What is causing the sporadic reset to 50W, and is there a write interval requirement for this path, or something else overwriting it?