The Dragonflight pre-patch interestingly has 2 splash screens, which could hint at pre-patch events starting at a later time.

Splash Screen 1 Text

Text in the first splash screen mentions UI updates, Dragonflight’s release date and the new talent system.

New in Dragonflight Pre-Patch!

User Interface Updates – The UI has undergone an art refresh. Customize it with the new Edit Mode!

Dragonflight Coming Soon! – November 28

New Talent System – Explore the brand new class and specialization trees and create your own talent build!

Splash Screen 2 Text

The second splash screen talks about the pre-patch events — Elemental Invasions and Uldaman returning as a Level 60 dungeon. It also mentions Dracthyr Evokers being available for play.

New in Dragonflight Pre-Patch!

Tempest Unleashed – Vanquish powerful elementals in storms that have erupted across Azeroth.

Uldaman – Brave the perils of Uldaman to secure the future of dragonkind.

Dracthyr Evoker – Azeroth’s newest race and class has awakened. Wield the power of the dragonflights to deal damage or heal your allies.