The known glitches in SWSH (recognized by Bulbapedia) are:
The Baton Pass Own Tempo Glitch-
If a Pokémon with Own Tempo is confused due to obtaining it from Baton Pass, it will not be cured of confusion until after a Pokémon takes its turn (uses a move, switches out, etc.).
Berry Tree Glitch-
This glitch involves shaking a Berry tree from behind. It ultimately allows for the player to walk through walls.
When a Pokémon is Dynamaxed, if the player looks at the party screen, the moves will be listed as if the Pokémon weren't Dynamaxed (Example: Rock Slide, Rock Blast, Sandstorm, Stone Edge). However, when checking the summary screen, the moves are displayed as Max Moves, in this case, Max Rockfall (three) and Max Guard.
Evolution Cancelling Glitch-
If the player cancels evolution of a Pokémon, the proper stamp will appear on the Y-Comm regardless.
Fairy Lock Crash-
In Pokémon Sword and Shield v1.1, if a Pokémon uses Fairy Lock while animations are enabled, the game crashes. Due to no Pokémon that can learn the move being present in Pokémon Sword and Shield at the time of this glitch's existence, the only way for this to legitimately occur is when the move is called via Metronome.
The crash does not occur if animations are disabled. This crash was not present in Pokémon Sword and Shield v1.0, and was fixed for v1.1.1.
A glitch which allows the player to move the cursor in a frame just before using an Experience Candy or starting an evolution. This applies the item/evolution sequence to the other Pokémon, and allows for major consequences such as evolving underleveled Pokémon (if the first Pokémon is of the same species), male Salandit, Combee (which become female Salazzle, Vespiquen), special event Pokémon that normally cannot evolve but can be forced to via level up and this glitch (involving event Meowth, Eevee) and Pokémon inside Eggs. If the species do not match, or evolution is impossible, the game may halt on an error message; closing the software.
The glitch appears to have been patched in v1.2.1.
Move Relearner Glitch-
These glitches occur when attempting to use a Move Relearner when there are at least 67 available moves (e.g. this can be done with a Mew which previously knew many Technical Records). It can cause the game to halt on an error message, closing the software. Other times, the player is able to see a glitched move (sometimes with a blank name, other times "———"). This glitch was found by SciresM.
Sucker Punch/Quash Glitch-
In a Double Battle where the player who didn't initiate the challenge is down to their final Pokémon, that Pokémon's Sucker Punch or Quash will fail when used against the opponent on their right. This applies regardless of what move the Pokémon selected for the turn. With the release of the version 1.1 update to Sword and Shield, this glitch was fixed and Sucker Punch and Quash can now correctly hit Pokémon in that position.
If an item can be consumed during switch-in, Symbiosis will activate it twice and consume the item that it passes.
Rose Tower Glitch-
This glitch occurs when the player flies to another location from the outside of Rose Tower before going inside the tower itself. The map shows the objective "Search for the bad League staff member hiding around Wyndon Monorail Terminal!" despite having already done so by this stage of the game. This area is no longer accessible and prevents the story from progressing as the player has no other means of going back to Rose Tower. This glitch was found by hikaribruh.
Ingredients Seller Glitch-
When the player cycles behind an ingredients seller he will turn around. He can then quickly go back round behind him and interact without him turning back again. When the player talks to him, his back will be turned to them.
List Item Glitch-
When the player finishes a Max Raid Battle induced by an event or Wild Area News, some list items will be shown separately.
June-July 2020 Wild Area News Event Glitches-
When the June 30, 2020-July 31, 2020 Wild Area News event began, it contained an error in which a nonexistent item was part of the item drops awarded for completing a Max Raid Battle tied to the event. The game attempting to reward the player with the nonexistent item caused a glitch that crashed the game after viewing the item drop list. This glitch was quickly fixed in two stages, first removing the nonexistent item from the item pool and then replacing it with the intended item, the Armorite Ore.
While the nonexistent item glitch was being fixed, another glitch occurred which prevented any Max Raid Battles associated with the event from being initiated while the game was connected to the Internet. This glitch was removed at the same time as the corrections to the nonexistent item glitch.
Hope this helps! :)