The RTX 2080 Ti was supposed to be launched on September 20 together with the RTX 2080, but, it seems that Nvidia had some inventory problems and had postpone the RTX 2080 Ti availability by a whole week. For those who managed to pre-order this model before it went out of stock, shipping will still occur between September 20 and 27.
https://www.notebookcheck.net/Nvidia-RTX-2080-Ti-availability-pushed-back-to-September-27.332234.0.html