[BUG] Can't remove Ecobee devices via the Integration

I'm still having problems with my Ecobee Switch+s where they don't poll their status (see Bug with Ecobee Integration and Switch+?). But I went into the Integration app last night because I noticed at some point I must have accidentally clicked to include my remote sensors through it (I use Ecobee Suite for my remote sensors). So I unchecked them in the app it resulted in the following error:

To reproduce:

1.) Go setup the Ecobee integration and add thermostats and sensors (I also added switches)
2.) Save everything, works fine
3.) Go back into the Ecobee integration and uncheck the thermostat and sensors

The error above occurs.