Disabling "Emit heartbeat" causes calibration problems

[alexcekay]

In the settings it is possible to disable the transmission of MAVLink heartbeats with the following button:

This will cause timeouts on the PX4 flight controller, which in turn will make it impossible to calibrate the magnetometer. The calibration of the magnetometer fails "silently", i.e. the panel with the 6 drone positions simply does not appear.
All this behaviour is very strange when first observed, and it takes a lot of time to debug the fact that the only difference between two setups is that the "Emit heartbeat" button is set on one system and not on the other.

To avoid a lot of debugging in the future, I have the following questions:

• Is this button required? What is the reason for the ability to disable heartbeats?
• Is it possible to display a warning or something similar that disabling heartbeats may cause unexpected behaviour on the flight controller?

FYI: @MaEtUgR