Blizzard have posted the known issues list for the Dragonflight pre-patch, from empty talent frames to AH issues, many UI problems and more.
Known Issues (Source)
The Dragonflight Pre-expansion patch is now live. Please read on for a list of known issues that we’re working on, and further information about this update
10.0.0 KNOWN ISSUES
Updated October 25
Classes
When logging into the Dragonflight pre-expansion patch for the first time, the Talent Frame and Action Bars may be empty. Logging out and back into the character should fix this issue.
The Micro Menu may flash with an indicator that something is undone, even after you’ve leveled and spent a talent point.
Covenant Abilities may not be properly replaced by their respective Talent, leading to the appearance of duplicates in the player’s spellbook. These Covenant Abilities and Talents will share a cooldown if either are cast.
Spells that have multiple charges via talents (such as Shadowstep or Healing Stream Totem) will not show their cooldown on the spell tooltip until you have at least 1 charge talented.
Auction House
Many non-PvP items are displaying the PvP item level marker while browsing. These items do not have PvP attributes.
Professions
The overall skill bar UI appears to be full regardless of your actual skill level.
When you drag invalid equipment over a Profession slot, an error can make the gear disappear and move to your normal character equipment slot.
The Reagent Bag slot is currently visible. This will be disabled and will return when players have access to Dragonflight Reagent Bags for this slot.
Newly crafted Profession items in the Dragonflight pre-expansion patch cannot be placed into Void Storage.
User Interface
Spells may not appear when placed, unless action bars are set to always show.
The Interact Key and Action Targeting Options may not be saved when you log out.
Abilities may incorrectly display on top of the action bar borders while cooling down.
Unit Frames may disappear, and then reappear when Edit Mode is activated. This may occur when the Unit Frame is anchored to the Extra Action Button.
The default placement for Group Loot Frame may cause items to move off screen. Use the command “/Reloadui” to fix this.
In the Group Finder, the Start Group button appears in the middle of the Custom category list.
Elite enemy nameplates do not include dragons, as intended.
Accessibility
Hold-To-Cast may not work with mouseover casting.
Melee attacks cannot be canceled by the Escape key with Action Targeting enabled.
Your Locked Target may be cleared when a different enemy Soft Target dies.
When using a Gamepad, button bindings can disappear from action bars.
User Services
When purchasing a Character Transfer, on the Select Destination Account step, you may notice the character in the dropdown appears to change to the first character on the character select screen. This is a visual bug, and your chosen character is still locked in from before.
Some NPCs who redeem codes from outside the game have been temporarily removed. They will return to their usual locations soon.
Website
WoW Armory web pages may display duplicated or missing Talents for specializations with multiple loadouts. This is a website display issue only and does not affect the game.
WoW Companion App
A bug can cause the Auction House tab to incorrectly display 0 currency and events on the Events tab to disappear. This may sometimes be resolved by logging out and back in.
For those just returning or who otherwise need to be caught up we have guides for both new and returning players.
New Player Help and Guides forum
Returning Player Help and Discussion forum
As with any update, it is important to make sure that if you use addons that they have been updated.
Helpful links for various tech issues:
Installation and Patching Troubleshooting
World of Warcraft Disconnection Problems
World of Warcraft Latency Problems