I’ve had this dwarf Alberta spruce for over two decades. One year, it sprouted a new shoot from the top. What caused this unusual growth?
Don’t worry your plant is fine. I have seen this happen to several plants throughout my career. Dwarf Alberta spruce, like many dwarf conifers, are propagated from a mutation found growing on a “normal” plant. The abnormal growth was propagated and sold as a unique variety. Occasionally a branch will revert back to the original species. Remove these as they appear to maintain the compact and unique appearance.