LIFX Built-in drivers - questions and discussion

Appreciate it -- one issue I'm hitting:

I try to run

String cmd = new hubitat.lifx.commands.SetExtendedColorZones(duration: tt, apply: APPLY_APPLY, zoneIndex: 0, colorsCount: hsbkList.size(), colors: hsbkList).format()

and get this error in the logs:

error groovy.lang.ReadOnlyPropertyException: Cannot set readonly property: duration for class: hubitat.lifx.commands.SetExtendedColorZones

If I remove duration, I likewise get the same exception on apply. Removing both, the packet is generated; but apply defaults to 0 (NO_APPLY), so the changes are not applied to the strip, just cached in the controller. Am I doing something wrong, or is this a bug in the implementation of this packet?