We’re told that the delay is only for the retail version of the lens. The 5D4 kits will ship on time. You’ll likely be able to buy a “white box” copy of the lens if you don’t want to wait.
After some investigation, a report at TDP suggest that the Canon EF 24-105mm f/4L IS II will be delayed until December. The lens was expected to arrive this week, but all indications suggest that will not be happening.
While the brilliant EF 16-35mm f/2.8L IS III shipped early, it looks like lightning won’t strike twice.