ADC-T3000 Thermostat Cycling

Over the last day, my ADC-T3000 thermostats have started short cycling my heater when reaching near the temperature setpoint. I’ve had these thermostats for a number of years now, and this is the first time I’m having this issue. I’m not getting any error messages or warnings such as System Protect other users complain about. How do I stop these thermostats from cycling my system multiple times per minute?

This is not a system issue, as when I remove the thermostat and connect Rh to W the heat works properly until I disconnect the wires from each other

When did this first begin yesterday?

I see there are 3 thermostats, do they control separate HVAC units?

On the thermostats I see a swing change setting of 1 degree, and an overshoot of 0. (1 thermostat has a swing of 1.5)

The swing temps look like they were recently edited. What were those previously?

A swing of 0.5 and an overshoot of 0 will guarantee the most frequent cycling, usually I recommend the swing to be 1.5 and/or an overshoot of 1 to run less frequently.

Still, there shouldn’t be multiple cycles in 1 minute. That sounds more like one of the Tstats is malfunctioning. You mention all of them plural but there are different Stage settings for one of them so I want to verify which thermostat you are referencing as having the trouble and what they all control.