Ignore this thread, I apologise I was wrong. What a great first contribution to the forum from me
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See below, that's my brand new Ableton Push 2 I've received a few hours ago

Track 2 "Grand piano" is selected and the button underneath is - correctly - white. Track 4 is not selected, so - if I understand how this works correctly - its button should be blue as for track 1 and 3, but it is violet instead. My Push has at least two of these issues, not sure I found all of them yet. It would be nice if someone with a deep experience of the Push wrote a "shopping list" of what to check in detail and how to do it.
In most countries you have the right to return the item to the seller within the first few days from purchasing. Checking the leds one by one before being too comfortable is definitely a check to do.
G.