Can't load filament to right nozzle during X/Y calibration wizard (Dual Extruder)

[caerandir]

If I start the X/Y calibration wizard from the touchscreen, I have the option to choose "Load filament". If I do so, I get to the nozzle control page and confirm heat up to 200°C. When nozzles are hot, I can load filament to the left nozzle, but if I switch to the right nozzle and press "Load", the "Load" and "Unload" buttons are greyed out and nothing happens. I can choose "Back" top left, say "Load Filament" again, buttons are no longer greyed out, but as soon as I say "Load" on the right nozzle, problem is back.

Workaround: Load filament via "Control" App before running the X/Y wizard.

Version 1.15.23