According to Hillier's: The new growth of H. ‘Gold Rush’ that emerges in spring is truly unique.
It initially displays shades of gold and flame orange, which then
mature to a rich golden yellow before turning green in the height of
summer. Its late summer flowers are large lavender blue/mauve with white
When you saw it a couple of weeks ago was it in a garden or a GC? If a GC then it may well have been deliberately held back (kept cold, or restricted daylight hours) so that it was still “doing its thing” at point of sale?